The Buttercup Chain

France and Margaret are cousins, born on the same day to twin sisters. They grow up feeling a bond as if brother and sister. When he returns to London from boarding school, France and Margaret make a pact in which each finds a suitable romantic partner for the other. But when they go away to the countryside with Manny and Fred, a strange incestuous impulse seems to exist between the cousins, while Manny also must deal with a pregnancy.