OUR FIRST STOP was for hot dogs and chocolate eclair cake at Portillo's. (Too bad I forgot my food diary at home.) Then we went to Navy Pier so I could see Lake Michigan and ride the Ferris wheel. The Ferris wheel ride was a bust; the fog was so thick in downtown Chicago that the buildings seemed to disappear into the heavens. But the visit wasn't a total loss. Warren bought me a puffy, bright blue winter coat that actually fit from a shop on the pier.

From there we took a cab north to visit Warren's old neighborhood, reasoning we could hit Millennium Park on the way back to the hotel. As we drove, my eyes were glued to the beach off to our right. Had I not known better, I would have sworn it was the ocean.

After a few minutes, we turned onto a street to our left and after several blocks, Warren tapped his finger against his window. "Sloan, look."

I followed the direction he was pointing. Up ahead was a church, that to my architecturally untrained eye, looked like a mini cathedral made out of bricks with stone trimmings. The main entrance had a huge arched doorway at the top of a wide staircase with a stone carved picture of God or Jesus or maybe Jerry Garcia, I had no idea. Beside the main building was a huge bell tower capped with a golden cross. My brain conjured up images of The Hunchback of North Chicago.

"At the curb is fine," Warren said to the driver.

"What is this place?" I asked as the cab rolled to a stop.

Warren opened the door and stepped out, then turned to offer me his hand. "St. Peter's Parish. This is where Azrael left me when I was born."

My eyes doubled in size. "Oh, wow."

As Reuel laboriously angled out of the back of the van, I ogled the building and Warren paid the fare. When we started up the steps to the glass entry, I looked up at Warren. "How long has it been since you've been here?"

He held the front door open for me. "Probably fifteen years or more." He followed in after me, passing the open door off to Reuel. "I came by here once in high school, to check it out. Didn't stick around though."

The door eased closed behind us, and once it was sealed, we were enveloped in the stoic silence of the tidy vestibule. The room was spacious and had two hallways that branched off either side. In the center in front of us, two double doors went into the sanctuary. Water trickled down a waterfall in a large stone fountain planted in the center of the room. On one of the rocks was a bronze sign that read DO NOT THROW COINS INTO THE FOUNTAIN. Beside it was a money collection box.

I peeked through the window in one of the doors into the sanctuary. On the left side was a tall statue of Mary and a table filled with candles. At the end of the center aisle was an ornate table and Jesus was crucified on the stone wall behind it. I never understood the use of the crucifix as a decorative fixture. Maybe it was a talking point or a visual think piece; it certainly didn't serve well as a marketing vehicle for me. Surely Jesus could feed a lot of hungry children with the dollars spent on carving out his most anguished moment in alabaster or soapstone.

Near the back, in one of the pews, a man was kneeling with his head bowed. And far to his right was another figure, dark in a red hat…

"May I help you?" The woman's voice was gentle, but it scared the bejeezus out of me. I screamed, and she jumped back a few tiles, grasping her heart. The tiny old woman with a helmet-shaped white hairdo was panting in front of a sign marked 'Offices.' She wore pleated tan polyester slacks and a white shirt under a pale yellow cardigan. Her wide eyes were magnified behind the thick lenses of her silver glasses as she struggled to catch her breath.

"I'm so sorry," I apologized, then quickly checked inside the sanctuary again. The figure was gone. Or maybe it was never there to begin with. "I didn't mean to startle you."

Warren touched my arm. "Are you all right?"

"Yes." No.

I took a deep breath and checked through the sanctuary door again. Nothing, except the old man praying in the back.

I stepped in the woman's direction and stuck out of my hand. "Hi. My name's Sloan."

"Ruby Riddle," she said.

"We're visiting from out of town, and my fiancé wanted to show me and our friend, Reuel"—I pointed to the hulking angel standing silently by the door—"the inside of the church. I hope that's all right."

She nodded and smiled warmly. "Of course it is. The sanctuary is open for prayer, or would you like to see anything in particular?"

I turned to Warren and turned my palms up in question. It was an awkward beat of silence.

"I was actually abandoned here when I was a baby." He awkwardly shoved his hands into his pockets and shrugged. "I guess I was curious to see the place again."

The old woman's crinkled lips parted and the slightest of gasps caught in her throat. We watched the blood drain from her face. "Warren?"

His back went rigid, and we looked at each other, shocked.

"I'm sorry. Have we met?" he asked.

Ruby cleared her throat. "Well, not officially. I've worked here for almost forty years." She touched her fingers to her chest. "I'm the person who found you."

My eyes bulged. "Shut up. Are you serious?"

She nodded. "Your first foster family brought you by here a couple of times asking for prayer, but you were tiny then. You must be thirty years old or more now."

"I'll be thirty in August," he said.

She sighed. "Three decades and I remember it like it was yesterday. I came in early that Monday morning to count the Sunday offering." She pointed back behind us. "Before I even got to that door, I heard a baby screaming. Of course, I ran toward the sound. The door was unlocked when I reached it, and when I got inside, I saw a bundle of blankets on the floor. Over there." She pointed beside the fountain. "The baby was kicking and thrashing its hands. I could tell it was in awful pain, but I didn't see anything wrong with it. I scooped him up and looked around. There was nothing. No note. No bottle. No diapers. Just this screaming infant in blue footed pajamas with a sailboat on the chest." She shook her head in awe. "I'll never forget it as long as I live."

Warren looked like he might be a little dizzy. "What happened then?"

"I called Father Warren first. He lived in the parsonage behind this building." She was pointing off in the distance behind us, but my eyes were set on my stunned fiancé.

"Father Warren," he repeated to me.

I raked my fingers back through my hair. "This is crazy."

Ruby continued. "Father Warren came and we decided it best to call the police. He took the baby, and I went back to my office because we didn't have cell phones back then." She gulped. "When I returned, Father Warren was bouncing the baby up and down, trying to calm him. Suddenly, he stopped bouncing and looked at me." Her face fell. "He said my name, then tensed up, and I grabbed the baby before he collapsed onto the floor."

A chill made me shudder.

"The doctors told us later it was an aortic aneurysm. He died before the ambulance got here."

"Holy shit." One hand reached to grasp Warren's. The other flew to my mouth, mortified by the obscenity. "Sorry."

Ruby obviously didn't care, at least not under the circumstances. She was still staring at Warren, mesmerized. I was staring at him too, but for a different reason. Warren knew how many deaths he'd caused in his lifetime. All were accounted for except one. His whole life he'd assumed the one he didn't remember had been his mother. However, if the priest had died while holding him, that would mean his mother's death hadn't been his fault after all.

"The priest died," I repeated.

His Adam's apple bobbed as his eyes slowly met mine.

Ruby continued on with her story, unaware of the news bomb she'd dropped. "You screamed until the lady from the state came to take you away." She lowered her voice. "We all wondered if your mother had been on drugs or something."

Warren nodded and looked back at her. "Something like that, I think."

Azrael had once compared the effects of us being separated from the supernatural to detox.

"But you're doing all right now?" she asked, folding her tiny hands into the prayer position beneath her chin.

"Better than all right." Warren flinched and reached into his pocket. He retrieved his cell phone. "It's Az," he said to me. "Mrs. Ruby, please excuse me." He pressed the phone to his ear and walked toward the door. "Hello?"

"Thank you for taking care of him," I said to her as she watched him across the room. "I'm sure it must have been frightening."

Tears spilled down her cheeks. "It was terrifying, but I'm so thankful he's doing well."

I slipped my arm around her shoulders. "Don't cry, Ruby. He's doing great. He's about to be a father Warren himself." With a smile, I patted my stomach.

She swiped her fingers under her glasses and laughed through her tears. "That's wonderful news. Congratulations."

"Thank you," I said.

Warren came back to us. "We've got to go."

Ruby looked around the lobby, then walked over to a rack holding brochures and pamphlets. She brought one over and handed it to him. "This has the main phone number for the church. Call me if you ever come back to town."

"I will. Thank you." Warren gave me the brochure. I folded it and tucked it in my purse.

She hugged me first, then Warren. When she pulled away from him, she let her hand linger on his chest, over his heart. "May I say a quick blessing over you?"

Warren's eyes darted toward me. I shrugged slightly to say "I guess."

He nodded.

I expected her to close her eyes, as they do in the protestant churches I'd visited back home. She didn't. She stared Warren right in the eyes. I wondered if it creeped him out at all. Then she began to pray out loud.

"Almighty God, who has commanded thy angels to guide and protect us, entreat them to clothe his children with protection unseen, to keep them from danger and preserve them from all evil. From this day till their last, grant them wisdom and strength, and be their rock of refuge that is quick to save. May they have confidence in your loving care, through Jesus Christ our Lord. Amen."

* * *

As soon as we were outside standing in the freezing cold again, I grabbed the sleeve of Warren's coat and stepped in front of him. I gripped both his forearms. "Warren, the priest died that night."

Unmistakable tears sparkled in his black eyes. "I know."

"Nadine's death wasn't your fault," I said, shaking him a bit.

He pulled me into his arms and heaved a heavy sigh of relief. "I didn't kill her," he whispered against my hair.

I could never imagine the weight that must have been lifted off him. That heartache had shaped him into the man he'd become, and in a moment he was absolved from it. I took a half-step back so I could look up at him. "See? Some good things do come out of Chicago."

He sniffed, but his tears never spilled from his eyes. "Maybe." He laughed and kissed the side of my head. "Come on. We have to go."

"Where are we headed?" I zipped my coat all the way up to my chin and tugged my scarf up around my mouth. The sky was gray with tufts of pillowy clouds that were drizzling tiny clumps of wet snow.

He offered me his hand as we neared the street. Reuel followed close behind us. "Az wants us to come to the factory building. He's found something he says we need to see."

My nose wrinkled. "I don't like the sound of that."

"Me either."

I jerked my thumb back over my shoulder toward the church behind us. "So that prayer…"

He looked at me. "Eerie, wasn't it?"

"Totally," I said. "I really wanted Reuel to bow and say something like 'Angel of Protection at your service.'"

All three of us laughed.

"Did you catch the 'protection unseen' bit of what she said?" I asked.

"How could I miss it?" His worried tone made me nervous. He looked both ways before leading us into the crosswalk. "What did you scream about in there? You almost gave that old woman a heart attack."

"Oh!" I almost stopped walking in the middle of the street, but he tugged me forward. "I may have seen that thing again in there."

"What thing?" he asked.

I nodded. "The thing from the train."

"What? Where?" As soon as we were safely on the other side, he stopped walking.

"Inside the sanctuary."

"Reuel, did you see anything?"

He shook his head.

"I think I saw it in the sanctuary when we first walked in," I said.

Warren closed his eyes for a moment. "I didn't sense anything like I did this morning."

"Maybe I imagined it."

He carefully scanned the area. "Let's keep our guard up. I need to ask Azrael who, or what, that could have been."

My face was chapped from the wind by the time we reached the "L" station. We passed a group of boys hiding behind the metal stairs up to the platform, and the sweet waft of marijuana widened all of our eyes. I wondered what Nathan would have said had he been there. When we reached the empty platform above and saw it was a four-minute wait for the next Green Line train, I decided to call him. I got his voicemail, but instead of leaving a message, I sent a text. Wanted to check in. Things are weird here, but no emergency.

A second later, the phone buzzed in my hand. It was a reply. No emergency? I'm shocked and a little disappointed.

Shut up, Nathan.

Nathan: LOL I'm on a call. Going to be awhile before I'm free to talk. Cool?

Me: Yeah. No rush. Everything's good here.

Nathan: Give my love to Warren.

I laughed. Will do. I'm sure he's missing you desperately.

"Nathan says he loves you."

Warren chuckled. "As gay as it sounds, I kinda miss him being here."

I tucked my phone into the fuzzy pocket of my new coat. "I'm sure he'd come if you asked him."

He crossed his arms. "Nah. I'm sure he's got plenty of loose ends to tie up at work."

"You're right. Ooo…I thought of the perfect cake for his party," I said, clapping my hands together.

"Oh yeah?"

"Yes! And I'm going to get Adrianne to plan the rest of it."

He raised an eyebrow. "Won't that deter her from planning our wedding?"

I laughed. "God, I hope so."

* * *

The old factory was a nondescript building next to an empty grass lot on one side and an abandoned print shop with a broken sign and graffiti-covered walls on the other. Had Marisol not mentioned the blue door, we would've lost it completely in the neighborhood camouflage of faded red brick and dirty mortar. Everything about the structure discouraged visitors, from the padlocked door to the crumbling entry step in front of it. A window on the ground floor was broken and boarded up like someone had tried to break in…or out.

Warren passed his hand in front of the padlock and it fell open. He twisted it and pulled it out of the latch, dropped it in his coat pocket, then pushed the door open. The inside of the building certainly didn't match its disheveled exterior. Aside from needing a thorough dusting, the office on the other side of the door was in perfect shape. It resembled the waiting area of a doctor's office or dentist.

I followed Warren inside and tried the light switch. Nothing happened. A wide hallway stretched out in front of us with a waiting area to our right and an office nook to our left. The waiting room was lined with gray padded metal armchairs. The white walls were bare and the only decoration was a small lamp on a side table. The office area had a light oak, L-shaped desk with a black rolling chair and a computer. I walked to the desk and found the workspace untouched, aside from a doodle in the corner of the desktop calendar. It was a child's drawing in black ink of a rainbow that ended in a heart.

"Sloan, this way," Warren said, walking toward the hall.

We passed a door with a handwritten sign marked "BATHROOM" next to a water cooler. At the end of the hall was another door, this one made of heavy metal with a steel handle and industrial deadbolt. There was a "DO NOT ENTER" sign taped to it with silver duct tape.

Warren waved his hand again and the lock tumbled. Reuel walked through first, but we stayed close behind him. It was a dark stairwell that led up to the next floor. I was latched to Warren's sleeve as we climbed the rusted metal stairs which had obviously been neglected during the remodel. Another metal door was at the top. It was unlocked.

"Finally," Azrael said, looking up from where he was hunched over a cardboard box that was sitting on a long white counter. "What took you so long?"

"We took the train," Warren said. "What is this place?"

I was wondering the same thing. The room was deep, with three long white work counters complete with sinks, cabinets, and rolling chairs. On the counter tops were computers, microscopes, test tubes, and machines I couldn't identify. In the corner was a row of pharmaceutical lab freezers like the ones in my dad's building at the hospital. "It's a medical lab."

Azrael nodded toward the wall to his left. There were three evenly spaced wooden doors along it. "There are hospital beds in those rooms."

I scratched my head. "Were they treating sick people here?"

He shook his head and held out a stack of folders. "I think they may have been creating them."

I crossed the room and reached for the folders. "Creating sick people?"

He leaned his arms on the counter. "I've been trying to figure out for months why they would form a prostitution ring."

"The money," Warren said like it was an obvious answer.

Azrael smirked. "That's not why they did it."

I flipped the first folder open. It was a medical chart. I'd seen enough of them in my father's office to not be completely lost. The patient was a twelve-year-old girl named Sofia. She tested positive for chlamydia (occupational hazard) and she was treated with azithromycin (failed to cure), doxycycline (failed to cure), erythromycin (failed to cure)…the list went on and on. Sofia's condition worsened to advanced pelvic inflammatory disease, and that's where her notes stopped. I opened the next folder. Natalia was fifteen. She, too, was treated several times unsuccessfully for chlamydia. The third folder was the same for a different patient.

Warren was reading over my shoulder. "They were treating the girls for STDs?"

Azrael held out an empty vial. "I think they were infecting them."

The label on the tube said Chlamydia Trachomatis - v29.

"What do you know about it?" Azrael asked.

"Wear condoms," I said.

Azrael scowled. "I'm being serious."

"I don't know anything about it, but I can ask my dad."

"Find out everything you can."

I pulled my phone out and sent my father a short text message. Need to know all you can tell me about chlamydia.

"Why don't you Google it?" Warren asked.

"That probably would be faster than—" My phone buzzed in my hand. "Or maybe not." I tapped the answer button. "Hey, Dad."

"Sloan, are you all right?" Dad's voice was full of alarm.

"What? Oh yeah. It's not me. I'm fine."

"Are you sure? An infection could have serious consequences for the baby if—"

"Dad! I promise," I said. "We're working on something up in Chicago and it's part of the case."

He paused. "Oh. Chicago?"

I walked toward the window and looked outside. "Yeah. Sorry, I should've let you know. We'll be up here for a day or two doing some stuff with the FBI."

He sighed into the phone. "I miss the days when your biggest work dilemma was a conflict on the county event calendar."

I smiled. "Me too."

"What do you want to know?" he asked.

"Hang on. I'm going to put you on speakerphone." I turned on the phone's speaker and walked back to where the guys were still searching through the boxes Azrael had opened. "OK, Dad. Tell me what you can about chlamydia."

"It's one of the most common sexually transmitted diseases. It's a highly infectious bacteria, but it's usually treatable with antibiotics," he said.

"Hi, Dr. Jordan. It's Azrael. What would make it not easily treatable?"

"Well, the resistance of chlamydia to antibiotics has begun stirring alarm within the medical community in the past few months. They've identified a couple of different multidrug-resistant strains that because of their reduced treatment options could have severe complications and long-term health problems, particularly for women."

"What kind of health problems?" I asked.

"Pelvic inflammatory disease, ectopic pregnancy, and miscarriage. If left untreated, it can cause sterility in both women and men."

Azrael knocked his knuckles against the counter. "That's it."

"Pardon me?" Dad asked.

Azrael held up the empty vial again. "How would it become drug resistant?"

"Bacteria can evolve and change so the drugs become ineffective. It's usually caused by overuse or improper use of antibiotics."

Azrael looked around the room. "What about bioengineering? Could it be created in a lab?"

Dad chuckled. "That's pretty far above my pay grade, but I'm sure it's possible with the right equipment and with people a whole lot smarter than me."

I suddenly felt really warm in my cozy jacket. I pumped the front of it to force cool air inside as I began to sweat nervously.

"Thank you, Dr. Jordan. That's exactly what we needed to know," Azrael said.

"Thanks, Dad. I'll call you later, OK?"

"All right, sweetheart. Be safe."

I hung up the phone and looked at Azrael. "You're talking about biological warfare."

He shrugged and looked over the paperwork spread across the counter. "Makes a lot more sense than pimping out little girls for money."

Warren ran his hands through his hair and looked up at the ceiling.

I felt sick as I picked up the small vial. "So now we know their master plan: use my baby to destroy the spirit line, then weed out all the humans."

"But what we don't know…" Azrael said.

Warren blew out a heavy sigh. "Is if they were successful."