Her name is Sarah. She's blonde, blue-eyed, and Jewish in 1939 Germany. And her act of resistance is about to change the world.

After her mother is shot at a checkpoint, fifteen-year-old Sarah meets a mysterious man with an ambiguous accent, a suspiciously bare apartment, and a lockbox full of weapons. He's part of the secret resistance against the Third Reich, and he needs Sarah to hide in plain sight at a school for the daughters of top Nazi brass, posing as one of them. If she can befriend the daughter of a key scientist and get invited to her house, she might be able to steal the blueprints to a bomb that could destroy the cities of Western Europe. Nothing could prepare Sarah for her cutthroat schoolmates, and soon she finds herself in a battle for survival unlike any she'd ever imagined. But anyone who underestimates this innocent-seeming girl does so at their peril. She may look sweet, but she's the Nazis' worst nightmare.
“A stunning, smart, grounded tale of intrigue in Nazi Germany, so guilty and detailed it feels like true memory rather than fiction. Sarah is an angry, appealing, heart-wrenching hero, superhuman and achingly frail in equal measure. I wish I’d written this myself. Deeply disturbing and chillingly good.”—Elizabeth Wein, New York Times bestselling author of Code Name Verity

 “I found myself mesmerized by Sarah’s journey into a world of human monsters. Orphan Monster Spy weaves one heroine’s courage through a spectrum of darkness, and the effects resonate long after the final page.” —Ryan Graudin, award-winning author of the Wolf By Wolf duology

“Killeen expertly conjures the day-to-day evil of Nazi Germany in this terrific page turner.”—Paul Dowswell, award-winning author of The Auslander

"A powerful, bleak, and penetrating portrait of an isolated young woman excelling in unimaginable danger."—Kirkus Reviews