What will happen to the greatest thief of our time when he finds himself out of time?

Following a lead from Fujiko, Lupin and Jigen excavate the sea floor in Kiritappu to search for a lost underwater treasure that supposedly holds the secrets of time travel. After the Lupin gang escapes a run-in with the law, a strange man calling himself Kyousuke Mamoh strands the Lupin gang hundreds of years in the past.