I should have gone straight home – work was over for the day. But something made me stop at the Renner property and make my way into the woods, although I can't say it was any sense that something extraordinary was about to happen. If anything, it was the opposite. I was too green, then, too inexperienced to know that when my fellow officers shook their heads and told me in baffled tones that they'd never seen anything like it, they were telling the plain truth. 'It' being, of course, the disappearance of Paige Renner, her newborn baby, her father and then her best friend Emma Wallis.

People going missing was nothing new. Young women going missing, especially, was nothing new. But not the way Paige Renner had gone missing, before reappearing with no coherent story to tell about where she'd been all those months – and then promptly disappearing again, that time with her baby son and her father. And then her best friend had gone, too, and literally nobody – including the cocky FBI agents who'd taken up residence in River Falls – seemed to have the first clue where any of them were. It didn't make sense. Not a single part of it made any sense. And the more the media and the amateur sleuths and the internet talked about it, the more they tried to turn the case this way or that, attempting to find some new angle from which to peer at it, the less sense it made.

I'd spent the afternoon tagging along with Marla Leigh, the improbably glamorously named FBI agent who had taken something of a mentoring attitude towards me after finding out I was not only new to the local police force in River Falls, but also the only female officer.

"Don't worry," Marla had said as we drove from the field office her agency set up in a nondescript office building back to the local PD's headquarters, "the FBI doesn't know what's happening, either. We're not keeping anything from you. At this point, I think my boss back in DC would be more than happy to hand over all the credit to anyone who could crack this case open. It's become a real resource-sucker, but nobody wants to be the one to make the call to pull back on it, you know?"

I did know. The public frenzy showed no signs of abating – if anything it was just getting more intense – and the FBI were as cognizant as my boss was of how easily sentiment could turn against law enforcement if we were seen to be slacking in any way.

"What do you think happened, though?" I asked as the car's rear tires skidded slightly on the gritty road and I clutched at the door to steady myself.

Marla slowed down and chuckled. "Jeez Louise, someone needs to sweep these roads! Now, what do I think happened? I don't know. I know what I don't think happened."

I nodded. "Yeah. Me too."

"And what don't you think happened?"

"I don't think this is one kidnapper at work," I said, as the first churnings of car sickness rumbled in my belly – Marla was one of those drivers who constantly switch between the brake and gas pedals, leading to a kind of gentle lurching that, if we didn't get to where we were going soon, was going to send my lunch flying. "I'm not even sure this is kidnappers at work at all. It doesn't make sense. Paige Renner came back. And Emma Wallis came back. And then they both disappeared again."

"It's baffling," Marla agreed, checking her steel-grey hair in the rearview mirror. "But if no one's been kidnapped, if there's no foul play – then what happened? You know as well as I do that these people genuinely seem to have disappeared off the face of the earth. No bank account activity, no cell phone records, no credible sightings – nothing. Normal people don't just up and decide to disappear – and these were by all accounts normal people. We've searched half the damn state with infrared-equipped helicopters, just in case they all decided to go live in the woods, we've combed through their internet records for any sign of grooming or cult activity. Nothing."

* * *

The woods on the Renner property were quiet, now that the FBI had designated the whole place a crime scene. The reporters and their trucks and lights and furry microphones were gone, too, back to the hotel in River Falls to track down ever more obscure people from the lives of the missing in the hopes that one of them, somehow, would be able to give some thorough and definitive answers to everyone's questions.

I circled the house once more, in the vain hope of spotting something that hadn't been spotted before. And then I laughed as I headed towards the trees – there was probably no more examined spot in all of America than the Renner house and its immediate surroundings – and yet there I was, half-convinced I was just going to stumble across a perfectly legible note sticking out from under a rock:

"Dear World,

In case you're wondering where we've all gotten to, well, here's the answer..."

There was no note. There was nothing in the woods, either. Well, I didn't think there was anything in the woods. Every inch of ground had been covered, the snow stomped down into the ground until almost none remained.

I stopped in the midst of the trees, bringing my hand up to shield my eyes from the sun's rays as it began to set and once again going over the facts of the case in my mind, still hopeful that something might pop up, some new thread to pull on.

Where did these people go? How can four people just disappear? What am I missing?

A loud crash brought me back to my senses and I turned towards it, preparing myself to deliver a forceful telling off to whoever it was trespassing on a crime scene. And then the words stuck in my throat as I stared, disbelieving at – at what exactly? At who?

A man stood in front of me. Not an ordinary man. Not a reporter I needed to threaten or a fellow police officer combing the woods one more time. No, this man was definitely neither of those things. I had no idea what this man was. He appeared to be dressed almost entirely in furs and leather and, for the briefest moment, my mind settled on the idea that he was on his way to a costume party.

But that didn't seem right, either. He was on foot in the country, miles from anywhere there might have been any costume parties happening in mid-January, and he didn't look like he was in costume. I don't know why I thought that, but I did. Something about him looked... real.

I stood about fifteen feet away, blinking at the apparition before me, my mind racing with possibilities that didn't really explain anything. I tried to speak. I tried to demand a name. No sound came from my lips. And then he smiled at me. And as he smiled he turned to the side, just a little, and the setting sun glinted off metal. A sword. The man beckoned me with one finger and took a step towards me.

I drew my gun immediately and held my ground, noticing it right away when the sight of my weapon didn't even make him flinch.

"Stop!" I barked, finding my voice again as he took another step. "Stop right there, sir! Show me your hands!"

He did not show me his hands. He didn't seem to have heard a single thing I said. And then he spoke.

"Don't run, girl. Ragnar is looking for –"

"STOP!" I shouted, my voice urgent, my finger slipping around the trigger. "Sir I don't want to shoot you! Please, stop!"

But he still did not stop. He advanced towards me quickly, with an odd half-amused, half-menacing expression in his eyes.

Anywhere else and I may not have done what I did. But I was on the Renner property – where four people had gone missing in the past five months. There was no way I was taking any chances with threatening men. And there was simply no time left. I took aim and squeezed the trigger.

I missed. I missed, but the sound of the gunshot was enough to stop the man in leather in his tracks. His eyes widened and he stared at the gun and I swear there was something about the bafflement on his face that made me think he'd never seen one before. But who doesn't know what a gun is?

"Stop right there!" I shouted, my voice quavering now. "I'll – sir, I'll shoot you. I don't want to but –"

Thankfully, he didn't make another move towards me. But just as I was about to command him to put his hands over his head, he suddenly whirled away from me, as if startled. Only there was nothing there behind him – just the woods, the Renner's fields, and a passing car on the road that ran alongside the property.

"Sir!" I yelled, angry at myself for having left my radio in my car. "SIR! Put your hands where I can –"

He wasn't listening. He was – what the hell was he doing? He was staring at something, frozen to the spot. Was he looking at the car? I couldn't tell. And it didn't matter. I needed to get control of the situation. Keeping the gun pointed at the man, who was still facing away from me, I pulled my phone out of my pocket and called my partner. It went to voicemail right away and I was about to call the office when the man turned back to me, wearing an expression I can only describe as shocked as his eyes alighted on my phone.

"Stay back!" I warned, but he was already stumbling away, turning to look at the road in the distance and then back at the phone in my hand repeatedly, until he eventually tripped on a log and fell on his ass.

"Sir?" I asked, not taking the gun off him but starting to think the explanation for his behavior – if not his outfit – was probably drugs. "Sir are you alright? Are you on any –"

"I'm with the gothi!" He said, although the comment didn't seem to be a response to my question. As he scrambled to his feet I asked him again if he was OK.

"I'm with the gothi," he repeated. "I must be with the gothi." And then, looking up at me again, he said that if he wasn't with the 'gothi' he needed to me to come with him. And when he addressed me that time, it was with a familiar name: Emma.

"Emma?" I asked, trying to keep my voice as calm and reasonable as possible. "You're looking for Emma? Emma Wallis?"

"Come with me," he said repeated, ignoring my questions and shaking his head. "I'm not with the gothi, am I? This is the world, the trees, I feel the chill in the air – come with me, Emma. Ragnar will see to it that you're punished for running away."

"NO!" I yelled, almost as exasperated as I was afraid by that point. I'd already shot at this man once – why was he coming for me again? But he was, and just like the first time, there was no hesitation. I clutched the gun in both hands, holding it aimed steady at the center of his body mass.

That time, I didn't miss. An anguished howl echoed through the woods as the man wearing furs fell back, clutching his left thigh and using his right leg to scramble awkwardly back, away from me. Seeing that he was mostly incapacitated, I looked down at my phone to dial 9-1-1.

"9-1-1 Emergency, how can I help you?"

I was panting, panicked, distracted by the cries of the wounded man – the one I'd just shot. I started to tell the dispatcher who I was, where I was and was just moving on to what emergency services I needed when it dawned on me suddenly that the forest was silent. I'd only looked away for a second, two at most. Hadn't I? The man had been using his good leg to push himself away from me, moving towards a tree and now he was – gone. He was gone.

"Ma'am?" The dispatcher's voice came down the line. "Officer Foster? Do you need –"

But I didn't hear the rest of it because my arm dropped to my side and I lunged forward, spinning around in a circle, opening and closing my eyes again. What was I missing? Where was he?

"Ma'am? Ma'am?"

I lifted the phone to my ear again. "Uh. Um – I –"

"Ma'am are you hurt? You said someone had been shot? Do you need me to send paramedics?"

"Yes," I whispered, more to myself than to the woman on the other end. "Someone has been shot. A – a man. I shot – I shot him. Someone –"

"You shot him, ma'am? Is he hurt? Do you need –"

I was running through the woods during that conversation, unable to comprehend the fact that he was gone – because he was gone. It was January, there were no leaves on the trees, no large boulders in the woods, no caves or hidden gullies to hide in.

"That's impossible," I whispered, turning in a circle once again, searching.

"I'm sorry what was that?" The dispatcher asked. "Is it possible? Yes, we can definitely send an ambulance if you need one. I'll send Jerry out, too."

Jerry Sawchuk was my boss, the River Falls police chief and a man I already knew was skeptical about the idea that a woman could be an effective police officer.

"No," I said. "No, hold on. Wait. I –"

"I'm sorry ma'am, I'm confused. Do you need an –"

I hung up, in a daze of confusion, and shoved the phone back in my pocket. Was I losing my mind? The sun was setting but there was still plenty enough light to see a full grown man in the woods. Except I couldn't see anyone. But I had, just moments before. Where the hell was he?

I stayed out there, tracing and retracing my own steps, checking behind trees that were no more than four inches wide, until Jerry Sawchuck and Dan Gardner – my partner – showed up about 20 minutes later.

"What happened?" Dan asked breathlessly as they ran towards me through the darkening woods. "Hey Sophie – are you OK? Dispatch said you shot someone?"

Both men, seeing that I was not in a life or death situation, were looking at me, waiting for an answer.

I looked up at Dan and then at Jerry. "I did."