小彤不愿意和想象朋友分开，而学校却禁止携带想象朋友。同时小彤的想象朋友吨吨也面临着消失的危机。在“成长”和“童真”之间，小彤左右为难。

Xiao Tong is unwilling to part with his imaginary friend, but the school just forbids him from doing that. At the same time, his imaginary friend Dundun also risks disappearance. Xiao Tong finds it so hard to reach a balance between "growing up and "remaining innocent".