Sporting Blood (1916)

Gambler Dave Garrison has caused the fury of James Riddle and Mary Ballard by seducing the former's sister Bessie and by deceiving the latter's brother Billy out of thousands of dollars. As a result, Mary and James join forces and come up with a plan to outsmart Dave. In effect, Mary bets herself against Dave's money, agreeing to sleep with the gambler if his horse, the favored Shooting Star, wins a race, while Dave must pay her $10,000 if the horse loses. To make the odds more in her favor, Mary switches horses, putting the lumbering lookalike May Belle in place of Shooting Star. As a result, Mary and James gain their revenge on Dave, after which, made confident by their good fortune at the racetrack, they decide to try their luck as husband and wife.