Amaama to Inazuma follows Kouhei Inuzuka, a math teacher who has been raising his young daughter Tsumugi alone since the death of his wife, Tae. Kind and devoted but lacking culinary knowledge, Kouhei leans on ready-made meals from convenience stores while trying to balance parenthood with his work at school. Frustrated by his own inability to put fresh, nutritious food on the table, he accepts an invitation from his student Kotori Iida to visit her family's restaurant for dinner.
Their first trip does not go as expected: Kotori's mother is often away for work, the restaurant is frequently closed, and Kotori herself often ends up eating alone. After much pleading from his pupil, Kouhei keeps returning with Tsumugi, and the three begin cooking and sharing homemade meals together. What starts as an improvised arrangement becomes the center of the series, turning everyday dishes into moments where Kouhei learns how to care for his daughter in new ways, Tsumugi finds joy in food, and Kotori gains a place where she does not have to eat by herself. The story builds its drama around family routines, cooking, and the warmth of meals at home.