Three senior high students - A-guo (阿國), A-long (阿龍) and Ren Xiu (仁修) - goes to a stream for fun before their university entrance exam. Beyond their imagination, A-guo drowns in the unpredictable water. By the time A-long and Ren Xiu they realize that, it is too late to save A-guo’s life. The story begins with a mock test scene, when Ren Xiu wakes up. Ren Xiu and A-long are frightened that the truth would be revealed someday. They begin to rely on and test each other. Because of the guilt for their friend and the accumulated stress, there is a subtle change in the friendship between the two. As time passes, Ren Xiu can't keep his feelings inside anymore and exploded.

任修，阿國和阿龍是同班同學也是同泳社的好朋友。一次的出遊，大家玩得不亦樂乎。當他們察覺是，才發現阿國已在溪里消失的無影無蹤了。為了脫罪，他們倆決定串通供詞。可是他們卻忘了，自己根本無法避開內心的恐懼與內疚...