Hardress Cregan is a young Irish aristocrat facing severe financial ruin. His mother, eager to restore their family's wealth and status, pushes him into an arranged marriage with a wealthy heiress, Anne Chute. However, Hardress is already secretly married to Eily O'Connor, a poor, beautiful peasant girl known as "The Colleen Bawn" (meaning "pure girl")

John Hare loses his job after attending a horse race without permission. Despite being married with a child, he invests his last shilling into a Tattersall's sweepstake ticket and ends up drawing the favorite. He then meets with Dick Fallows, the owner of the horse, and places two-thirds of the sweep money with him. The horse wins, but after Hare secures the prize money, he returns to Fallows' camp where he deals with the subsequent fallout and comedic twists surrounding the winnings.