Sara Martinez is a hacker. She recently broke into the New York City foster care system to expose her foster parents as cheats and lawbreakers. However, instead of being hailed as a hero, Sara finds herself facing years in a juvenile detention facility and banned from using computers for the same stretch of time. Enter Mother, a British spy who not only gets Sara released from jail but also offers her a chance to make a home for herself within a secret MI5 agency. Before she knows what she's doing, Sarah is heading to Paris for an international youth summit, hacking into a rival school's computer to prevent them from winning a million euros, dangling thirty feet off the side of a building, and trying to stop a villain, all while navigating the complex dynamics of her new team.