One evening, Mouri, Ran and Conan are at Mihua hotel. When they are having supper, Conan notices a man near their table anxious. Through his talking to mobile phone, Conan infers his son is kidnapped.
They followed the man to his home and Mouri intends to help him. The man accepts his help but refuses to call the police lest his son should be killed. During the talking, Conan puts a tracker on the man's bag.
The next day, he receives a call from the kidnapper. He is required to add more money and wait at the station at 12 o'clock. He also heard his son's voice saying: "so many crabs ' a whale is spurting water" There is only 2 hours left. Mouri, Ran and Conan go everywhere to look for crab and the child. But find nothing, and the time is coming.
Mouri and Ran go to the station. And see the kidnapper riding a motorcycle. He managed to get the money bag. Though Mouri tries to catch him, he immediately drives away. But the number of his motorcycle is recorded by Mouri's camera. It seems his identity will soon clear.
The other way, since Conan has put a tracker on the bag, he taps his glasses and a map appears on it. He follows the location, finding the bag laying on a pile of rubbish, already empty. Together with the bag, is a license plate of a motorcycle. Now all the clue disappear.
Since the kidnapper has already get the money, next, he will kill the child. Conan is so anxious. Then he remembers the whale-shaped publicity airship and sees the tall chimney smoking. If the airship float to the line which the chimney and the watcher make, it maybe likes spurting water. To get that effect, a person must see the whale from a high place. Conan runs to Mihua hotel, and rushes into the lift. When it goes up, Conan notices that the chairs and tables on the downstairs ground seem like many crabs.
It mustn't be wrong, the child is indeed here. When the kidnapper is about to leave with the child, Conan subdues him.