Ian (Ewan McGregor) is a dreamer with his sights set on building hotels in California and wooing a beautiful young actress. Terry (Colin Farrell) is a mechanic who drinks far too much and fancies a flutter all too often. The London working-class brothers struggle to live the comfortable life they yearn. When Terry has a big win one day the brothers buy a watch - "Cassandra's Dream" - and it seems their long-term dreams may actually come true. Soon enough however Terry finds himself in dire trouble with a massive gambling debt and loan sharks breathing down his neck. He and Ian approach their rich and generous Uncle Howard (Tom Wilkinson Michael Clayton) asking for a loan with a promise to pay him back. But Uncle Howard has something else in mind - "a little favour". With a business associate about to blow the whistle on him jail is a likely outcome. He needs the brothers to dispose of the associate - and their debt will be paid. It is a price neither brother anticipated they would have to pay - and at a cost they could never have imagined.