“This is my daughter, Nina,” her mamá murmured.

Samantha trotted over to her father and tugged at his hand. “Dad, can Nina come over again soon?” she pleaded.

The king turned his warm eyes on Nina’s mamá. “Samantha is right. I hope you’ll bring Nina here in the afternoons. After all, it’s not like we have a short workday.”

Isabella blinked. “Your Majesty?”

“The girls clearly get along, and I know your wife has a busy schedule, too. Why should Nina stay home with a babysitter when she could be here?”

Nina was too young to understand Isabella’s hesitation. “Please, mamá?” she’d chimed in, brimming with eagerness. Isabella had relented with a sigh.

And just like that, Nina was interwoven into the lives of the royal twins.

They became an instant threesome: the prince, the princess, and the chamberlain’s daughter. Back then Nina hadn’t even known to feel self-conscious about the differences between her life and Samantha’s. For even though they were twins, and royalty, Jeff and Sam never made Nina feel like an outsider. If anything, they were all equally excluded from the glamorous and inaccessible world of the adults—even from Beatrice, who at age ten was already enrolled in private tutoring on top of her middle school courses.

Sam and Jeff were always the instigators of their plans, with Nina trying and failing to keep them in line. They would escape the twins’ nanny and set out on some escapade: to swim in the heated indoor pool, or to find the rumored safe rooms and bomb shelters that were supposedly hidden throughout the palace. One time Samantha convinced them to hide beneath a tablecloth and eavesdrop on a private meeting between the king and the Austrian ambassador. They were caught after just two minutes, when Jeff tugged on the tablecloth and knocked over a pitcher of water, but by then Samantha had already squirted honey into the ambassador’s shoe. “If you don’t want honey in your shoes, don’t kick them off under the table,” she’d said later, her eyes gleaming with mischief.

The fact that Samantha and Nina’s friendship had survived all these years was a testament to the princess’s determination. She refused to let them drift apart, even though they went to different schools, even after Nina’s mamá left her role as chamberlain and was named Minister of the Treasury. Samantha just kept on inviting Nina to the palace for sleepovers, or to the Washingtons’ vacation homes for holiday weekends, or to attend state events as her plus-one.

Nina’s parents had mixed feelings about their daughter’s friendship with the princess.

Isabella and Julie had met years ago in grad school. By now they were one of Washington’s power couples: Isabella working as Minister of the Treasury, Julie the founder of a successful e-commerce business. They didn’t argue very often, but Nina’s complicated relationship with the Washingtons was something they never managed to agree on.

“We can’t let Nina go on that trip,” Isabella had protested, after Samantha invited Nina to the royal family’s beach house. “I don’t want her spending too much time with them, especially when we aren’t around.”

Nina’s ears perked up at the sound of their voices, which echoed through the building’s old-fashioned heating pipes. She was in her bedroom on the third floor, beneath the attic. She hadn’t meant to eavesdrop … but she’d also never confessed how easily she could hear them when they spoke in the sitting room directly below.

“Why not?” Julie had replied, her voice oddly distorted by the old metal pipes.

“Because I worry about her! The world that the Washingtons inhabit, with all its private planes and court galas and protocol—that isn’t reality. And no matter how often they invite her or how much Princess Samantha likes her, Nina will never really be one of them.” Nina’s mamá sighed. “I don’t want her feeling like a poor relation from some Jane Austen novel.”

Nina shifted closer on her mattress to catch the response.

“The princess has been a good friend to Nina,” her mom protested. “And you should have a little more faith in the way we’ve raised our daughter. If anything, I think Nina will be a positive influence on Samantha, by reminding her what exists outside those palace gates. The princess probably needs a normal friend.”

Eventually Nina’s parents had agreed to let her go, with the stipulation that she stay out of the public eye and never be quoted or photographed in press coverage of the royal family. The palace had been happy to agree. They didn’t particularly want the media focusing on Princess Samantha, either.

By the time they were in high school, Nina was used to her best friend’s quirky plans and contagious excitement. Let’s take Albert out! Sam would text, naming the lemon-yellow Jeep she’d begged her parents to give her on her sixteenth birthday. She had the car, but she kept failing the parallel-parking part of her driver’s test and still didn’t have a license. Which meant that Nina ended up driving that obnoxiously yellow Jeep all through the capital, with Samantha sitting cross-legged in the passenger seat, begging her to swing through McDonald’s. After a while Nina didn’t even worry about the protection officer glowering at them from the back.

Sam made it far too easy for Nina to forget the myriad differences between them. And Nina loved her, without strings or conditions, the way she would have loved a sister if she’d had one. It was just that her sister happened to be the Princess of America.