In the 30th century, time travel becomes illegal after a time paradox crisis. The Time Protection Department is established to watch for and stop time crimes. Four new enlistee cadets of the TPD are tricked by Don Geltzer and his gang into letting them time-travel to the 21th century to commit various crimes. To protect history, the four cadets pursue them. There they encounter a severe problem: the Time Patrol Ranger program requires five members for the first operation. They thus coerce a present-day martial artist, Kasey Stones, to join them, allowing them to become the Time Patrol Ranger.
Over time, the four cadets begin to realize that their presence would inevitably change the future in the form of the City Guardians, a security force under the employment of the Stone Corporation to protect the city from the Mutants.
