As a child, Nao Okura loved nothing more than being beside her mother when she made wagashi: traditional Japanese sweets. Her mother found a live-in position as a wagashi maker at Kogetsuan—a shop that had been founded over four hundred years ago—and it was there that Nao met the heir to the shop, Tsubaki Takatsuki, a radiant boy who filled her childhood with light. The warmth and love of those days, however, comes to an abrupt halt when tragedy strikes, and Nao's mother is arrested for a crime she didn't commit, with Tsubaki's testimony landing her in jail.

Fifteen years later, Nao—now living as Nao Hanaoka—is working as a wagashi maker at a reputable establishment, though soon her path leads her back to Kogetsuan and Tsubaki. The formerly cheerful boy has grown into a cruel man, and Nao's encounters with him show that very little of her friend remains, and that he doesn't seem to recognize her. Shockingly, Tsubaki asks Nao to marry him, believing her talent can change Kogetsuan's wagashi for the better. Nao agrees, wishing to use the situation to get access to Kogetsuan and find out the truth behind what really happened 15 years ago. So begins their marriage of convenience, but could it ever turn into something more?