The Sister in Law (1974)

Robert and Edward, two brothers entangled in a scandalous affair, find their lives spiraling out of control. They juggle Edward's wife and his mistress while embarking on a perilous journey to smuggle a package of jewels across the Canadian border. However, their seemingly simple mission quickly escalates into a deadly game of betrayal and deceit, testing the limits of their brotherhood and moral integrity. As tensions rise, both men must confront the consequences of their choices in a gripping tale of infidelity and danger.