Charlie's Aunt Fifi is fatally poisoned by a mysterious figure. Jean discovers that the deceased owned valuable antiques and collectibles, potentially making Charlie an heir. However, Fifi's complicated relationship with her half-sister Ines and her husband Alan may jeopardise that. 

Jean is contacted by couple Margot and Bobby, who believe they possess the original blueprints of Valletta, the capital city of Malta, designed by Jean de Valette himself. They invite the pair to authenticate the plans in Malta. When Jean and Dom land at the Malta airport, things take a sudden turn as they witness two figures fleeing from Margot and Bobby's car. To their horror, Margot has been struck, and blood pours from the back of her head. As Jean and Dom inspect the Jean de Valette statue, they meet with Inspector Agius at Margot and Bobby's antique shop. Bobby suggests Jean contact Colin, another dealer interested in the blueprints. Will Jean uncover the mystery behind Margot's attack, and are these blueprints authentic?