The true story of Christopher Gardner, who invests heavily in a device known as a 'Bone Density Scanner', only to find himself struggle to sell the product as it's just marginally better than the current technology, and much more expensive. His wife leaves him, he loses his house, bank account and credit cards and, now forced to live out in the streets with his young son, he's desperate to find a steady job. He takes on a job as a stockbroker but, before he can receive pay, he needs to go through 6 months of training, and must sell his devices.