The most renowned blue sapphire, dubbed the "Blue Lapis Fist," is rumored to have sunk aboard a pirate vessel in the late nineteenth century off Singapore"s coast. A wealthy local schemes to recover it, and when the gem is displayed at an exhibition in Singapore"s Marina Sands hotel a murder occurs. A blood‑stained Kaitou Kid announcement card is discovered at the scene, and the gem"s legend has drawn attention from collectors worldwide.
Meanwhile Ran and Sonoko arrive in Singapore to attend a karate contest. Conan, lacking a passport and barred from overseas travel, was meant to stay home. Yet Kid, intent on exploiting him, employs a sorcery trick to force Conan into Singapore. To return to Japan, Conan must obey Kid; he is stripped of his glasses, watch, clothes and other belongings, and forced to conceal himself. Conan must also disguise his identity by adopting a new persona.
Ran, unaware of Conan"s true identity, asks for his name; Conan fabricates the alias Arthur Hirai. Kid finally learns that the "Fist" is kept in an underground vault beneath a manor. Just as he believes entry will be simple, he encounters a deadly trap. Opposite him stands the toughest karateka, Makoto Kyogoku, who boasts 400 consecutive victories.
