迪杰（泰伦斯•霍华德 Terrence Dashon Howard 饰）是一个皮条客， 每天和妓女诺拉（塔恩•曼宁 Taryn Manning 饰）在汽车上接客，日子极为无聊，深感中年危机。在一次黑市交易中，迪杰买到了一个卡通电子钢琴，唤起了自己关于唱诗班的回忆。他得知嘻哈巨星凯尼布莱克（卢达•克里斯 Ludacris 饰）将在7月4日开演唱会。他希望能够录自己的demo小样，寄给这位嘻哈界的大腕。于是，迪杰开始重新组建乐队，找到昔日唱诗班的老友凯（安东尼•安德森 Anthony Anderson 饰），白人钢琴师布莱尔，孕妇莎戈（塔拉吉•P•汉森 Taraji P. Henson 饰）等人帮忙，一步一步实现着自己的理想。他把自己底层生活的经验变成了歌词，用激情荡漾的演绎，征服了媒体和乐迷，然而正当他即将大红时，却因为一次莫名其妙的官司锒铛入狱……...
When Watson reads from the newspaper there have been two similar murders near Whitechapel in a few days, Sherlock Holmes' sharp deductive is immediately stimulated to start its merciless method of elimination after observation of every apparently meaningless detail. He guesses right the victims must be street whores, and doesn't need long to work his way trough a pawn shop, an aristocratic family's stately home, a hospital and of course the potential suspects and (even unknowing) witnesses who are the cast of the gradually unraveled story of the murderer and his motive....
