International man of mystery Diabolik and his sensuous lover Eva Kant pull off heist after heist, all while European cops led by Inspector Ginko and envious mobsters led by Ralph Valmont are closing in on them.

1960s, the city of Clerville. The forthcoming visit of heiress Eva Kant, who'll be bringing a famous pink diamond with her, catches the attention of Diabolik, the infallible and elusive thief whose real identity is unknown: while trying to steal the jewel, he finds himself bewitched by Eva's charm, a feeling she may be reciprocating. But the police, led by relentless Inspector Ginko, is rapidly closing in on him...

Diabolik narrowly escapes Inspector Ginko's latest trap, leaving his partner in crime Eva Kant behind. Furious, Eva offers Ginko her help in capturing him, but the former has to face first the return of an old flame of his, noblewoman Altea.

Captured by a ruthless gang of bank robbers, foes Diabolik and Ginko find themselves facing certain death. While Eva Kant and Altea forge an unlikely alliance to rescue their lovers, Diabolik reveals his mysterious past to the Inspector.