在这部不能说的夏天剧情片中,23岁的白白（郭采洁 饰）怀揣着纯洁而又热切的音乐梦想，只身一人远赴音乐学院深造，充满了自由和新鲜空气的大学校园让长久以来生活在压抑之中的白白第一次体会到了什么叫做真正的快乐。在学校里，白白遇见了英俊的学弟木宏（黄远 饰），两人意气相投，彼此之间距离越来越近。
白白的单纯和可爱勾起了李教授（戴立忍 饰）对于自己岁月往事的回忆，受到欲望和占有欲的控制，李教授利用职务之便和年龄上的优势，将白白诱惑进了一段背德的师生恋情之中。恋情曝光后，社会、网络舆论如同排山倒海般席卷而来，涉世未深的白白该怎样负担这沉重的一切？
22 year old Bai arrives in a small town of Taiwan to pursue a Masters degree in music. She is quickly involved in a weird relationship with her teacher, Lee, which slowly turns into a dominated dependence. One night, Bai's friend, Mu-hung, a young innocent student tells her his feeling and tries to kiss her. That same night Bai tries to commit suicide. A diagnosis of Post-Traumatic Stress Disorder makes Wang, a teacher of the University, decide to help Bai. Wang's old friend Fang, a notorious shyster, steps in. While the entire University takes the side of Lee, Pai herself is confused and not sure if Lee did something wrong. But Wang and Fang decide to get justice for her.
并非所有的受害者都会大声呐喊。青春不是大篷车。《寒蟬效應》：噤若寒蟬。寒蝉效应/不能说的夏天 对照的真实新闻事件记录。此蝉声甚悦。细腻中带着煎熬。被侮辱与被损害的。《不能说的夏天》：让蝉声渐响。《不能说的夏天》公益放映会，与监制徐小明先生交流笔记。。蝉声虽响 奈何乱。
