《开学悸》由《伤疤》、《相见》和《自习室》三个故事组成，以风靡一时的真实校园怪谈为题材，使这些古老的传说在不同的时空中重现活力。影片以女生桃子独自在自习室等待男友的场景展开，男友在电话中给桃子讲了两个校园中的恐怖传说，直到两个故事结束，男友都没有出现，而与此同时，一个黑影正从桃子的身后慢慢接近她，就此展开了影片的第三个故事。
在系列终章中，幸存者们将面对蒙面陌生人的新威胁。随着秘密浮出水面，现实与危险的界限逐渐模糊，他们的生存之战也愈发凶险。
An old woman, Filomena, is hurried into the emergency room. The young man, who brought her, Matias, is very nervous. The nurses were drawn to him as he’s very good-looking. They think he’s her grandson. Filomena’s condition has stabilized but she needs further tests. At night, Matias visits her and Luna, the nurse on duty, is touched at how warm and close Matias is to the lady....
On a quest to find the father she thought was dead, a determined young girl uses a mysterious device that allows travel between worlds but unknowingly unleashes a monster from one of those worlds that haunts her every step.
两名潜水者发现了昆特小船的残骸，并在拍照时命丧鲨口翌日，警察局长马丁·布洛迪接到报告，有人在附近水域发现了一艘无人游艇，布洛迪指派手下进行调查并找回失踪者的水下摄影机。与此同时，一名正在滑水的女子葬身鱼腹，驾驶快艇的女子将油箱抛向鲨鱼，并用信号枪引燃，鲨鱼燃烧起来，而快艇也在爆炸中四分五裂，不过，身负重伤的鲨鱼还是逃脱了。因为找不到遇难者遗体，布洛迪开始心生疑虑。一条鲸鱼在海滩上搁浅，布洛迪推测是鲨鱼袭击所致，海洋生物学家埃尔金斯虽然持怀疑态度，但她承认鲨鱼会被血液、运动和声音吸引。布洛迪认为可能还有一条大白鲨存在……
