Twenty-three years ago, Sumi Otonashi was killed in a mugging gone wrong. Or was she? Out of nowhere, her husband Goichi reveals to his heirs that he killed her—and challenges them to figure out how. But can they reach a plausible explanation without knowing he contracted a spectre to do the deed? And what will their own buried secrets bring to light? Kotoko will have to judge the heirs' solutions, and lead them to the right answer ...