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Single father Kōhei struggles to cook tasty and healthy meals for his daughter, Tsumugi, after his wife passes away. It's not until his encounter outside of school with one of his students, Kotori Iida, that he's able to leave ready-made meals behind as the three learn how to cook together in the Iida family's restaurant.
Tsumugi and shellfish on Chapter 37 of the manga series.