Darien Lambert, Captain of the Fugitive Retrieval Section in the 22nd century, time-travels to the 20th century to capture 22nd century criminals who have escaped by time-traveling. He is armed with a PPT, a 3-button weapon that can render a man unconscious or send a man to the 22nd century. He has a computer named Selma, disguised as a credit card. Selma helps him to capture the fugitives, for she has access to various databases, and can make logical conclusions. She has also many other functions. The main criminal is Mo Sahmbi, who invented the time machine (TRAX) and helped the criminals to get away. Lambert cannot go to the 22nd century until he has captured all the fugitives.