Main character decides to help his childhood friend and classmate Momoka with her summer homework. He promises to make three wishes come true if everything is done in time. To his surprise Momoka remembers this promise and suggests having a date at an amusement park. The second request is a kiss on a Ferris wheel. Protagonist proposes third wish himself by unzipping his pants. Naughty lessons continue from there.

[From vndbreview]