[Machine Translation] The 2A Detective Bureau has been asked to catch Marriott, the thief who is causing a commotion in London! Ariki, Shinnosuke, and Mitsugi go to London! However, the thief's real target is the world's largest diamond belonging to the British Royal Family! Ariki and the others board the Queen Elizabeth, a luxury liner carrying the diamonds, but...? All the members of Bokura also gather! 2A & Bokura face off against the thief! The first special story in the Tsubasa Bunko 2A series! From elementary school upper grade.