Although Wu You (Huang Xiaoming) has reached an advanced age, his IQ and cognitive level still remain at the level of a child. As his name suggests, he is as carefree as a child and curious about the world. Wu You is single and lives with his optimistic mother, Shen Liping (Lu Xiaofen). He becomes a senior partner in a success organization called "Sunshine Club" when his mother falls seriously ill. While his brother Wu Di (Zu Feng), a doctor, tries his best to cure his mother, Wu You chooses a very different path to save her. He firmly believes that as long as you let the sun shine inside, there will always be a miracle in life ......

电影《永安镇故事集》是一部“关于电影”的电影，叙述了一个剧组入住拍摄地，给这个原本宁静的小镇带来一丝波澜，然而波澜过后，一切又重归宁静的故事。影片分为三个章节——独自等待、看上去很美、冥王星时刻，小镇和剧组串联起三个章节的故事和其中的人物——与小镇格格不入的饭店老板娘、回不去故乡的女明星、陷入创作分歧的导演与编剧……因为剧组的到来，每一个置身这座小镇的人心中都荡起一丝涟漪，但涟漪终会散去，一切也终将重归平静。

20世纪90年代，江南某个小镇。阴郁的河边，幺四婆婆被人残忍杀害。好大喜功的警察局长（侯天来 饰）定了调子，此案一定追查到底。刑警队长马哲（朱一龙 饰）带着徒弟小谢（佟林楷 饰）对死者周边关系展开调查，得知老太太生前与人为善，还收养了一个疯子（康春雷 饰）。而从疯子这里，似乎又找不到更多的突破点。丢失在现场的女士书包引起马哲注意，通过包内的磁带，他找到了女包的主人及其相关者，但依旧捋不出头绪。局长认定疯子就是凶手，应该尽快结案。可就在此时，新的死者出现了…… 本片根据余华的同名小说改编。