While her brother and son are out hunting, Queen Sakura of Vespania is shot. The prince finds her and apparently shoots himself in guilt. This makes the news, which is how Detective Conan hears about it, along with a report that valuable minerals have been found in Vespania. Meanwhile, Lupin has flown into Vespania. With the death of the queen and prince, the young but bratty Princess Mira is next in line. However, there is a popular movement in Vespania that says the princess is too young. Duke Keith hires Jigen as the princess' bodyguard, who uses his access to scope out the Queen's Crown for Lupin, which is protected by a formidable array of sensors.