The O'Leary family are traveling to Chicago to start a new life when Patrick O'Leary tries to race a steam train in his wagon. He is killed when his horses bolt. His wife Molly and their three boys are left to survive on their own. In town she agrees to prove her skills as a laundress when a woman's dress is accidentally spattered with mud. She quickly proves herself and builds up a laundry business in an area known as "West Town, Chicago#Smith Park". Her sons are educated. One, Jack, becomes a reforming lawyer, but another, Dion, is involved in gambling. While washing a sheet, Mrs O'Leary discovers a drawing, apparently created by Gil Warren, a devious local businessman. Her sons realize that it reveals that he has a plan to run a tramline along a street that he and his cronies intend to buy up cheaply.