Toiromachi is a small mountainous town by the sea that's slightly distanced from the big city. The story begins in a long-standing restaurant in the heart of its shopping district called "Murasaki", which serves eel dishes.
The restaurant is flourishing thanks to the happily married couple that run it; the proprietress is popular in the neighborhood while the skills of the restaurant owner, who is also her husband, are well-regarded. Their only daughter and this story's protagonist is a normal university student you'd find anywhere. She doesn't have anything in particular she wants to do and is spending her summer holidays mulling over what to do for her next part-time job.
One day however, her hardworking mother collapses and the protagonist becomes Murasaki's substitute proprietress! In the middle of summer, a highly profitable period, she's made to manage the shop while it's understaffed. Though she's only be covering until her mother is discharged from hospital, a lifestyle completely different from the one she's lead so far has begun!
On top of that, she accidentally finds a single letter addressed to her mother...
"That child... That girl I gave birth to... I wonder if she has been well?"
"I'm not Mom and Dad's child?!"
Confused and bawling her eyes out, a boy suddenly flies down from the sky and appears before her...
As hectic and busy days go by, all of the mysteries gradually unravel. Followed by a strange boy as she navigates the complicated interpersonal relationships between her peers, will this otherwise normal proprietress and student be able to solve the mysteries of her life?