A millionaire covets the world-famous "Blue Lapis Fist", a sapphire rumoured to have sunk with a pirate ship off the coast of Singapore in the 19th century. But when the gem is exhibited at the Marina Sands hotel, a murder occurs and a bloody Kaitou Kid announcement card is discovered at the scene. Meanwhile, Ran and Sonoko are in Singapore for a karate tournament while Conan is stuck behind without a passport. Kid uses his magical abilities to transport Conan to the crime scene, and in exchange for a safe return home, Conan helps Kid steal his own belongings and assumes the alias of Arthur Hirai. Kid discovers that the "Blue Lapis Fist" is hidden in an underground vault in a wealthy estate, but must defeat a formidable opponent, Makoto Kyogoku, a karate master with an unbeaten record of 400 victories.