The series follows Kimizuka Kimihiko, a young man who is always getting into trouble, as he finds himself the assistant of Siesta, a globe-trotting detective, and the two of them solve a series of mysteries.
But after years of adventuring and saving lives, Siesta mysteriously dies, though her legacy will shape the lives of Kimihiko and others as they move forward.
Set in 1921 during the Taisho period of Japanese history, the story follows Tamahiko Shima as he is shuffled out of sight by his father after a freak accident causes Tamahiko's right arm to become disabled. Now living in the Japanese countryside, Tamahiko discovers that his father has purchased a bride to look after him: the elegant, beautiful, and very young Yuzuki Tachibana, a girl who brings light back into Tamahiko's dark life
Yaotome's the cute president of the shogi (Japanese chess) club at her high school, and she's pretty sure that her underclassman Ayumu, the only other member, has a huge crush on her. They get together to play shogi every day after school, but no matter what she does, she can't seem to coax or trick him into confessing his feelings! What she doesn't know is that Ayumu has made a pact with himself to reveal his love after he's beaten Yaotome at shogi for the first time. Yet there's one big issue with this plan...he really sucks!