Yuka, a teacher at an all-boys school, is giving summer classes to students who had poor grades in the first semester. Watching Kawaguchi, who is particularly struggling among them, Yuka's maternal instincts are aroused and she makes a promise to motivate him. "If you study hard and get good results, you can kiss me!" Kawaguchi's motives were impure, but his academic performance improved rapidly. "As promised, I'll give you a reward!" Yuka says as they kiss each other...