Kimihiko spends the entire show mourning someone already gone, solving mysteries that only deepen the wound instead of closing it. The genius move is making the murder of your partner the premise, not the climax, so every answer about her death costs him something new. A show about a man trying to move on that refuses to let him, because the case won't stop following him home.

Kimihiko Kimizuka keeps getting dragged into crimes, and one day he is taken aboard a flight that gets hijacked. There he meets Siesta, a silver-haired girl who calls herself a legendary detective, resolves the crisis and insists he become her sidekick. Their partnership turns into three years of adventures around the globe, facing syndicates and threats to humanity, until Siesta suddenly dies. Kimihiko tries to put her memory behind him, but a new case ties him to an assassin, a worldwide conspiracy and his late partner, and he meets a girl who looks strikingly like Siesta. Adapted from a light novel series, the show mixes mystery, comedy, romance, drama and supernatural elements.