The Apprentices — Maile Meloy

It's 1954, and Janie Scott is in boarding school in New Hampshire, trying to make a new life. Two years have passed since she last saw the mysterious apothecary -- or his defiant son, Benjamin. All she knows is that her friends are out there somewhere, trying to keep the world safe in an age of mounting atomic power. On the other side of the world, Benjamin is treating the wounded in a jungle war, and experimenting with a magical new formula that will let him communicate with Janie across the globe.

But Janie has her own experiment underway, and it's attracting interest from sinister forces. Benjamin calls on their friend Pip for help, and they have to race to find one another, and to unravel the mystery of their powerful new enemies.