"Together, four people from the year 3000 and a man from our time write a new chapter in history...."―Opening narration[src] 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 Dolnero and his gang into letting them time-travel to the 20th century to commit various crimes. To protect history, the four cadets pursue them. There they encounter a severe problem: the Timeranger program requires five members for the first operation. They thus force a present-day martial artist, Tatsuya Asami, to join them, allowing them to become the Timerangers. Afterwards Tatsuya rents a building for them to live in and they start a small odd jobs business called Tomorrow Research to financially support themselves. 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 Asami Corporation to protect the city from the Londerz. The City Guardians gain a tenuous relationship with the Timerangers, especially when Tatsuya's old rival Naoto Takizawa becomes TimeFire and later the City Guardians' Captain. In the series finale, the Timerangers go back to their regular lives. A year later Tatsuya is jogging when he sees five people who resemble the other Timerangers (including Naoto), but realizes it isn't them.