Cross My Heart and Hope to Spy

by Ally Carter

I know you just finished Carter, but hear me out—this one trades the boarding school setting for a completely different flavor of spy craft. Katarina Bishop is a con artist rather than a trained operative, which means the tension comes from improvisation and cleverness rather than protocol, and the ensemble cast of misfits has that same witty banter you loved without the school structure constraining them.

by Trenton Lee Stewart

This one captures that same feeling of ordinary teenagers discovering they're part of something much bigger and more dangerous than they realized. Stewart builds his mystery with the same careful layering Carter uses—you're learning the rules of this world alongside the characters, and there's genuine stakes beneath the adventure. The found-family dynamic between your protagonists will feel familiar, but the puzzle-box plot is entirely its own thing.

by Margaret Rogerson

This is my gentle push toward something with more magical atmosphere—but it's got the same DNA as Gallagher Girls: a girl attending a secretive academy where she's learning skills she didn't know she'd need, surrounded by dangerous secrets and a boy who's not what he seems. Rogerson writes romance with real tension (the way Carter does), but she layers in gothic atmosphere and actual peril that makes the stakes feel weightier.

by Ian Fleming

I'm recommending this 2022 novel because Roberts does something interesting here: she writes a spy thriller with the emotional intelligence and character work you loved in Carter, but aimed at adult readers. The protagonist is a woman running her own operation, and Roberts uses that same technique of gradually revealing how much danger everyone's actually in while maintaining genuine humor and warmth in the relationships. It's what Cammie's world might look like ten years later.

by Elizabeth A. Johnson

Johnson splits her narrative between a modern-day girl at a prestigious boarding school and a cold case from the 1930s, and what makes it brilliant is how she uses the school's secrets and traditions to slowly unravel a real mystery. Like Carter, she trusts her readers to piece things together, but she adds this layer of historical intrigue that gives the boarding school setting unexpected weight. The protagonist is clever and resourceful without being superhuman, and the friendships feel earned rather than instant.