Ahead of the Kiss. Volume 1

Fumino Kaji, a schoolgirl with a younger brother, is found by her homeroom teacher Kazuma Odziro on the street, who offers to take her to live at his home. The girl claims that if he feels so sorry for her,
then he should marry her. Thus, word leads to word, and the two really get married! At first, Fumino decides to use the sensei only to support her brother, but thanks to Kazuma's love, she also begins to develop certain feelings for him…