Shinichi and some friends he met at his new school have gone to a museum. When coming out, he tells his three friends, Ayumi (Amy), Genta (George), and Mitsuhiko (Mitch), about there being undiscovered treasures, most of which is gold bullion. Genta wants to find those treasures and his wish may be granted, when a slip of paper comes their way. Ayumi thinks it could be a treasure map, which leads them on a journey.
Shinichi gets frustrated not knowing how to decipher the paper and Ayumi has the idea that it could be the signs. However, they get into big trouble with the clothing stores in the area the paper takes them to.
When they could not find any more signs, Shinichi has the idea of finding the symbols in neon lights.
Meanwhile, a group dressed in black is chasing the kids. Shinichi notices their presence from the first time they arrived near Tokyo Tower, but he does not know of their intention to find the same treasure that the kids are looking for.
Arriving at the final stop, Shinichi, Ayumi, Genta, and Mitsuhiko find gold. However, they are stopped by the same people who were following them. After knowing who they really were and what they were after, Shinichi comes up with a plan to catch these criminals.
