Manabu Yukawa, a university professor known as "Detective Galileo," travels to Hari Cove, a once-popular summer resort that is going through hard times. He is there to participate in the presentation of an underwater mining project that deeply divides the local inhabitants. One faction opposes the proposed development, concerned about the environmental impact on the area, known for its pristine waters. The other faction, which sees no future for the town as it is, believes its only hope lies in this development project.
The night after the tense roundtable, one of the resort's guests turns up dead on the seashore at the foot of the area's cliffs. At first, the local police believe it was a simple accident: he fell off the cliff while walking on unfamiliar terrain in the middle of the night. However, when they discover that the victim, Tsukahara, was a former police officer and that the cause of death was carbon monoxide poisoning, they begin to suspect that he was murdered and his body thrown off the cliff to mislead the police.
While the police try to discover where Tsukahara was murdered and why, Yukawa becomes interested in an old murder case that has already been solved, but with confusing aspects. After a series of complex and surprising twists and turns, as in Higashino's other works, Detective Galileo discovers the hidden relationship behind the tragic events leading up to the murder in Hari Cove.
The morality corresponds to the society of the early 21st century, with characters tormented by a past that they have to hide. A guilt weighs heavy with no way to obtain forgiveness. The characters grow up in a culture where personal guilt is not related to a God who offers channels for forgiveness. It highlights the value of friendship and the ability to sacrifice for the loved ones.
The language is delicate and there are no immoral descriptions.