近未来的美国，全国失业率仅为1%，犯罪率则创下史上最低纪录，暴力几乎消失无踪。美利坚合众国仿佛进入宛如天堂的美好黄金时代，而促成这完美表象的则是前所未闻的大扫荡计划。国家为了有效释放公民心底的压抑和不满情绪，特别规定每年有一天的晚上7点之后举行长达十二小时的全国性大扫荡，届时人们将走上街头，展开完全不用承担法律责任的殴斗与杀戮。在这个畸形的时代，安保系统推销员詹姆斯·桑丁（伊森·霍克 Ethan Hawke）大发其财，与妻子儿女过着养尊处优的幸福生活。又是一年大扫荡之夜到来，桑丁一家端坐固若金汤的豪华府邸，在屏幕前观赏杀戮之夜的表演。谁知这一晚，詹姆斯的儿子查理出手拯救了一名被追杀的流浪汉，桑丁一家不可避免被卷入血腥的漩涡之中…… ©豆瓣

Antonio and Nikola are inseparable friends who live across the road from each other, and share a love of pyrotechnics and mobile phones. Their families have been in dispute for years over an easily resolvable problem: the water that flows from the top house to the bottom house. The boys’ friendship, as they are about to enter puberty, is put to the test at Christmas time when their families uncover much more dangerous secrets and interests, and the water just carries the hate of the adults to the children.