The manga follows the strange and often dangerous operations of Tsukumo, an antique shop of a very particular kind, for it is a place where wishes come true. The shop is run by Satori, a mysterious and powerful ayakashi who has the ability to read human hearts and is driven by an insatiable hunger to consume them. Living with Satori is Adashino, a high school boy who possesses a unique constitution that allows him to see ayakashi that are invisible to normal people. Their relationship is not a simple employer-employee one; Adashino is effectively kept by Satori like a pet, used as bait to lure in other ayakashi that Satori can then devour to satisfy his hunger for human hearts.

The narrative unfolds as a series of mysteries, with each new customer who enters Tsukumo presenting a strange wish tied to a supernatural affliction. As Satori and Adashino work together to address these cases, the story delves into the core mystery surrounding Satori himself. He was born without a heart from a sealed pit where discarded emotions and even the bodies of sacrificed children accumulated. Because of this, Satori, who can see through everything else, is unable to perceive his own heart. He consumes other ayakashi in a desperate attempt to fill this emptiness.

Adashino is forced to act as the reluctant companion in this quest, and over time, the nature of their relationship begins to change, from one of convenience to a deeper bond. A key character is Saku, a tsukumogami who was causing disappearances out of loneliness after losing her master. Instead of being destroyed, Saku is taken in by Adashino, becoming a source of light and a new resident of the shop. A significant narrative arc involves a Karasu Tengu who once sought to befriend Satori. The Tengu, after being rejected, later provides Adashino with three critical hints about Satori's origins, his condition, and his obsession with hearts. The central conflict revolves around whether Adashino can help Satori recover or understand his missing heart before the ayakashis hunger consumes them both, especially as Satoris inability to perceive his own feelings causes him to act in arrogant and often self-destructive ways. The story typically returns to the mysterious shop Tsukumo, which acts as a fixed point between the mundane world and the supernatural, as each customer's wish leads them deeper into the nature of hearts and desires.