An aged father known to everyone as Old Liu (played by Zhu Xu) and his younger, mentally challenged son Liu Erming (Jiang Wu) run and live in a traditional bathhouse for men in an old district in Beijing. The bathhouse provides a variety of peripheral services, including haircut, massage, shaving, fire cupping, even old-style pedicure, to a motley group of regular customers, many of whom are retired old Beijingers. The patrons usually spend their entire day, day after day, in the bathhouse, engaging in a game of Chinese chess or cricket fighting. As such, they have formed close bonds not only with one another, but also with Old Liu, who is manager, staff, mediator in squabbles, and marriage consultant all in one. One of the patrons is a man who sings '"O Sole Mio" in the shower, but when he goes to sing it in public he loses his ability, until Erming provides him with a shower from a hose. Another patron is Mr. Zhang, whose marriage has been in trouble ever since his wife ran after a thief while naked, and Old Liu arranges a reconciliation by having the man find his wife in the bath. After the bathhouse closes in the evening, Old Liu and Erming go for their daily jog around the neighbourhood, after which they engage in a contest to hold their breath in water as they bathe. Even simple tasks such as cleaning up the bathhouse are tremendous fun for the duo, both of whom behave like little children at these times.