Chen Mo (played by Chen Xuedong) and Mo Han (played by Jiang Wen) are lovers who have been dating for many years and have a very good relationship with each other. The two live in the same apartment with another couple Le Yi (played by Zhang Yixing) and Lu Mijia (played by Li Xiaolu), and often get together to play. Although the four are adults, their personalities are still as carefree as children. They eat, drink and have fun all day long, without any responsibility, and never think about the future. One day, a baby who suddenly appeared fell into the four people like a meteorite, causing a big explosion. Four adults who have no experience in taking care of babies are forced to become nannies and are tossed around by a little person. What makes the four people even more incredible is that this seemingly innocent baby actually has a shocking special ability. As time goes by, the four people and the baby have established a precious family relationship.