故事发生在2007年的香港。在迎接08年奥运的大环境下，影片讲述一群临近中五会考的中学生之间有关成长的青春故事。一部手机短片，一连串的荒谬事件，引发了九个少男少女之间的矛盾冲突。本来的信任依赖，渐渐发展成了彼此的猜忌与摩擦。站在懵懂与长大的十字路口，这些孩子们面对着友情与爱情的双重考验。而随之而来的家庭问题和现实世界的真实残酷，九位少年又当如何应对？青春的故事有很多，影片用幽默跳脱的手法细细讲来。

《烈日当空》是由曾志伟监制的两岸三地“九降风”系列同名电影的香港篇。

The Hong Kong chapter of Eric Tsang's "Growing-up Trilogy" bears testimony to the saying: "The kindness of the gods is manifested in allowing young people to embark on life unprepared." Heiward Mak, the 23-year-old director whom people in the inner circle repute to be the next shining star of Hong Kong cinema, crafts a string of vignettes about seven young people about to sit for a major public exam. Clever, humorous, angry and dangerous, this is the Cruel Stories of Youth for the Me Generation of this century of globalization and mediocrity