Wake, Chao and Ace want to go on a trip during their summer vacation, but their vacation spot turns out to be a half-abandoned, mysterious town that is filled with creepy sailor stories and seems to harbor an ancient secret.

Her teacher dies in a fall from the school stairs and bequeaths Wake a mysterious chest, the contents of which lead her, Chao and Ace on the trail of a mysterious legend and into a nerve-wracking adventure.

A tsunami destroys a nuclear power plant (again), but this event seems to be connected to the mysterious footprints that Ass discovered during his visit to his cousin in the countryside. Wake and Chao help him unravel the mystery, unaware that the three of them are putting themselves in great danger.