该片为1974年的经典恐怖片《德州电锯杀人狂》的前传电影。影片讲述四个精神病犯人从精神病院逃出，并绑架了一名年轻的护士，他们一起踏上了血腥残酷的旅程。追在他们身后的，是一对精神错乱的德州骑警。

湿冷无望的哥谭市，卑微的亚瑟·弗兰克（华金·菲尼克斯 Joaquin Phoenix 饰）依靠扮演小丑赚取营生。与之相依为命的母亲患有精神疾病，而亚瑟深记母亲的教诲，无论遭受怎样的挫折都笑对人生，却因此让自己背负着莫大的压力，濒临崩溃。他梦想成为一名脱口秀演员，怎奈生活一次次将失望狠狠地砸在他的头上。不仅如此，他因意外丢掉了工作，偶然瞥见母亲的秘密，又使他心中燃起对那个与之地位悬殊却从未谋面的父亲的殷切渴望。命运习惯了事与愿违，空荡荡的地铁内，悲伤的小丑在无法自已的癫狂笑声中大开杀戒……                                                                      　　本片荣获第76届威尼斯电影节金狮奖。

　　供职于某银行信贷机构的美丽女孩克莉丝蒂安（艾莉森•洛曼 Alison Lohman 饰）经过多年的努力，事业终于有所起色；她和男友克雷（Justin Long 饰）的恋情虽遭对方母亲的反对，却也是情投意合，顺风顺水。可是，一场无妄之灾将她的人生推向谷底。
　　住在布雷顿大街的吉普赛老妇人希尔维娅•加纳什（Lorna Raver 饰）因医疗纠纷面临房产被收回的困境，克莉丝蒂安同情她的遭遇，无奈规定所限无能为力。愤怒至极的加纳什迁怒于无辜的克莉丝蒂安，两人在车库中发生激烈搏斗，加纳什更向对方落下无情诅咒。在接下来的日子里，克莉丝蒂安遭遇诸多恐怖和离奇的事件。她决定拜访加纳什解决这一切，却发现老妇人已经去世。而魔鬼黑山羊的诅咒仍在继续……

　　January is forced to return home after six years traveling abroad. A near-fatal accident has left her temporarily wheelchair bound and depleted of her long-term memory. She is accompanied by her boyfriend 'Callum' whom she met whilst traveling. He was also the driver in the fateful accident. Not only has she forgotten her family, but her childhood as well and is surprised to discover that her home is a stately manor in the middle of the country-side. As January tries to settle in, she finds herself becoming even more estranged from her family, who just want their daughter back. The trouble is, she cannot remember who that daughter was, or why she ran away in the first place. Desperate to discover why she left all those years ago and with Callum's help, she sets out to find the truth. They soon discover the family are not as loving as they seem to be. Was there a dark reason why she left them in the first place?