Lupin attempts to steal a royal crown from the fictional country of Vespania after its owner, the queen, is assassinated by her son, who then shot himself. Jigen infiltrates the National Guard as a sharpshooting instructor, while Fujiko tails the princess, on holiday in Japan. Meanwhile, Conan Edogawa saves the princess, who looks exactly like his friend Ran, from an assassination attempt. Inspector Zenigata teams up with Kogoro Mouri to catch the assassin and foil Lupin's scheme. Fujiko kidnaps the princess while leaving Ran to act as her double. In the end, Conan and Lupin have to team up to find out the truth behind the assassination and save the princess from the same fate