When Rowan Stillwell writes the future by accident, she learns some events don’t wait to be erased. Rowan Stillwell has always believed the antiques in her shop remember more than they should. When a stranger sells her an unremarkable fountain pen that never runs dry, Rowan expects nothing more than another curiosity to catalogue. Instead, the pen begins to write on its own—recording disasters before they happen, sealing moments that should still be uncertain. Fires burn. Lives end. And Rowan is forced to confront a terrible truth: some events are not created by fate, only finalized by it.

Fresh from their Egyptian adventure, twelve-year-old Juno Jones and her friends—the Chronos Crew—are still learning to balance normal middle school life with their secret roles as Time Guardians. But when a corrupted temporal portal suddenly opens in their headquarters, they're forced to make an impossible choice: face capture by the sinister Tempus Corporation, or leap unprepared into Renaissance Florence with a terrifying deadline—return within 27 hours or be trapped in 1610 forever.