Ryuji likes pachi-slot, and often goes to the pachi-slot parlor. He meets Satoru there, and they become friends. One day, Satoru loses his wallet, and begins to live at Ryuji's place. Yuuto, who works at a convenience store near the parlor, falls victim to fraud, and is dumped a lot of debt. To run away from it, Yuuto secretly starts living at Ryuji's place. Takami, who is a university student, is attacked by someone unknown, and runs into Ryuji's place. Ryuji tells him to stay at his house for a while to hide himself from the attacker. Takami reluctantly accepts his offer, and four boys start living together....