Oshima Yuka, a married female teacher at an all-boys school, decides to hold summer remedial classes for students who performed poorly in the first semester. Focusing particularly on Kawanishi, one of the lowest achievers, she makes a special promise to motivate him: "If you work hard and show results, you can kiss me, your teacher." Though Yuka's intentions aren't entirely pure, her offer spurs Kawanishi to gradually improve his academic performance. When he finally meets the promised results, Yuka fulfills her end of the bargain and locks lips with him.