Dan Mahowny (Philip Seymour Hoffman) is a mild-mannered bank manager with a nasty gambling habit and a job that gives him access to a $20 million account. When a major losing streak leaves him busted and unable to cover his losses, Mahowny develops an ingenious plan to play the bank against the casino. But with time running out and the odds stacked against him, obsession becomes compulsion and the thrill of the bet is quickly replaced with a primal desire to stay in the game. Based on the true story of the largest one-man bank fraud in Canadian history.