Simon Carrerra has just been released from prison and is now on parole. His old pal Albert entices him to renew his career in crime with a big - time heist of a celebrated diamond in Antwerp. This involves a mafia - style boss and a complicated robbery in a luxury hotel in Antwerp during the auction of the diamond.
The "Florentine" is an historic jewel owned by Marie Neuville and her daughter Julia, two diamond experts. Marie Neuville's sudden death puts Julia in charge of the sale. Because she's young and inexperienced, she'll encounter some flack. But, she's determined.
In Antwerp, Simon, posing as a friend of her mother's and an expert in security, meets Julia. Slowly but surely, the two become closer... perhaps too close... He manages to get a double to the key, essential for the robbery.
Simon has no choice but to betray Julia. The heist is a success. However, Scylla unexpectedly enacts a hidden part of his plan. He gets rid of his accomplices and makes it look like the diamond has disappeared in the ocean during what seems to be vengeance murder.
But Simon and Albert escape the massacre in extremis. Discovering that Julia is being accused of complicity and that the death of her mother was linked to Scylla's gang, Simon decides to take action: He'll help Julia get the diamond back and avenge her mother's death...