Mister Jerico: The Britannia Film Collection DVD

Expert con artist Dudley Jerico and his sidekick Wally set out to rob the famous Gemini diamond, owned by corrupt South American millionaire, Victor Rosso, who is obsessed with obtaining its twin. Jerico has, in his possession, a perfect copy of it, which he offers to sell Russo.

A carefully-planned burglary enables Jerico to switch diamonds, however, before the deal can be done, Rosso tells him that a Mademoiselle Claudine has called from Pars saying she has the twin of the Gemini diamond to sell him.

One of them is lying... but who is it?