Treasure

Naoyuki, a sincere and honest country boy, moves to Tokyo to attend high school and stays with his cousin's family. Everyone around him, including his college-age cousin Satoshi, initially takes advantage of his naive and trusting nature. Satoshi even demands that Naoyuki have sex with him in exchange for tutoring.

As time passes, Satoshi realizes that Naoyuki is not as gullible as he appears and begins to fall in love with the boy's pure-heartedness. A new schoolmate also develops feelings for Naoyuki, leaving him confused about his own emotions and struggling to understand the difference between sex, love, and friendship.