An accident on the playground makes Yan Shuo, a quiet but observant boy, and Tu Wei, a passionate and outspoken boy with a bit of a willful streak, become friends. Learning that Yan Shuo had lost his mother at an early age and that his father had neglected him, Tu Wei's family sympathized with and cared for this studious and hard-working child. As Yan Shuo becomes a regular guest of Tu Wei's family, he realizes that the seemingly harmonious and happy Tu Wei family actually has their own knot in their hearts, and Yan Shuo's arrival also brings a different kind of vitality to Tu Wei's family life. Late one night, Tu Wei's family receives the news of Yan Shuo's father's accidental death. Faced with the sudden change, Tu Wei's parents decide to formally accept Yan Shuo as a family member. The destinies of the four people are intertwined.