Mamo Kyosuke claims that Lupin will disappear from the world in four days. He claims that he is a time traveller from 2874 seeking revenge. Apparently, Lupin XIII destroyed the Mamo clan on March, 2874. Kyosuke has travelled back in time to destroy Lupin III and prevent his clan's future destruction. Kyosuke backs his claims up by travelling into the past and killing the builder of a castle causing it to disappear in front of Lupin's eyes.