Mr Steel, a wealthy but extremely old man, has decided to transfer his brain to a younger body and attain a second youth. He has the perfect body in mind for his brain transplant: Arsène Lupin III; and the perfect person to handle the affair: Lupin's lover, Fujiko Mine. Fujiko manages to capture Lupin through a faked traffic accident, and brings him to Steel's mansion, where the brain transplant takes place successfully. The old man has only a little time left, but the brain is Lupin's, and he embarks on a plan to get his old body back...
—Tenchi