TimeRiders: Gates of Rome (Book 5)

In the fifth installment of the bestselling TimeRiders series by Alex Scarrow, three individuals who narrowly escaped death are tasked with preventing catastrophic disruptions to history through a secret agency. When a mission to alter the Roman Empire goes awry, the team finds themselves stranded in ancient Rome during Caligula's reign, facing new dangers and the challenge of returning to their own time. With history hanging in the balance, their adventure explores the perils of time travel and the fight to set history right.