Pei-pei is a junior high girl, who is often trapped in the classroom with Yi-shian, a boy hardly seen around school. Though they are in the same classroom, they are in two different worlds.

One day, a failure in competition makes Pei-pei feel awful. Through Yi-shian’s encouragement, she climbs over the school’s fence to explore a new world.

Pei-pei has a hard time to keep calm because of constant depression and anxiety in her puberty. There is no exit to vent her forbidden desire and voices that should not be heard. Is the outside world really as wonderful as she imagined? Will Pei-pei be able to find the way after crossing the wall?

文靜乖巧的霈霈與調皮的以翔是同班同學，但個性迥異的兩人看起來似乎來不同的世界。

一天，在比賽中失利的霈霈經過了以翔的開解，她成功地將自己帶到了一個全新的世界裡。

課業上與青春期的壓力讓她陷入了自我的封閉與失落，到底她能否翻越這道高牆嗎？