They came in the middle of the night. Because of course they came in the middle of the night. They always do, don't they? Why the US government sent agents to England, eight-year-old Sam Whitby didn't know.
The one in charge seemed nice. Suspiciously so.
Colonel Scott Sandoval told Sam that he was special, and that they were going to a place for special kids. That Sam would make friends.
Sam wouldn't make many friends. Not that he wasn't used to it already. It was just him and his mother.
Sam only agreed to go when Sandoval said Sam's classmate and neighbor, Alexis Wilde, was going, too.

Back in America.
Seven-year-old Fee Curtis was an orphan. She didn't want friends. She didn't want a family. She didn't need either.
When Colonel Sandoval and his agents went to retrieve her, she went kicking and screaming. One of the agents ended up dying from the injuries Fee inflicted.

Ten-year-old Michael Marcus, nine-year-old Leo Santiago, and eight-year-old James Reese only vaguely knew each other from living in the same town.

Initially, 42 different special groups of children would be tracked down by Colonel Sandoval. This trio would be the only known exception to the "one child per specialty" rule he'd set up.

Eight-year-old Agustín Cordes was the last child to go with Sandoval. His town was small enough that he'd heard Sandoval was coming before he showed up.
He snuck out of the house to willingly go before his parents could say anything. He'd heard his parents worrying earlier that day.
He had a gut feeling that it wasn't going to be a safe place he was going to. But he would make it one for the other kids, or die trying.

Somewhere just outside Washington, DC.
There were 44 white vans carrying 44 children towards what looked like a boarding school.
Once inside, the 44 children were separated into what were more like cells than dorm rooms.
They were now prisoners of the CIA.