Three chapters, of which two are on the main story. For his 16th birthday, his father gives Keito a surprising present: an elder "brother"! Code-named K-5, this "brother" is a robot whose only function and order is to love Keito. Not having grown up with Keito, K-5 doesn't know the boundaries of brotherly love. How is Keito to handle his relationship with his new girlfriend while trying to deal with his possessive "brother"? The third chapter's a oneshot on a girl who puts on a smiling, obliging smile of a mask no matter what her classmates demand from her.

Based on the play-by-mail game Hourai Gakuen (story by SHINJOU Kazuma).