Zhou Dayou, a cleaner, goes out for a drinking party, leaving his autistic daughter, A Yue, locked inside their home. Frightened, A Yue climbs onto the balcony searching for her mother, loses her footing, and falls, ending up hanging from an air-conditioning unit frame on the fifteenth floor. Lao Lin, whom Zhou Dayou once framed and wronged, puts aside his personal grudge and risks his life to rescue A Yue. Overcome with guilt afterward, Zhou Dayou turns over a new leaf, gives up drinking, and works hard. To raise money for his daughter's rehabilitation, he dismantles the door to repay his debts and publicly admits his wrongdoing, clearing Lao Lin's name. Eventually, the two join forces to establish a housekeeping company. The Zhou family is reunited, and Lao Lin becomes their most important family member.