House of Numbers (1957)

Arnie Judlow, an inmate at San Quentin prison serving a life sentence for murder, devises a daring plan with his wife and his brother Bill to help him escape, part of which involves Bill and Arnie's wife posing as a married couple and moving to a house near the prison. Although the plan appears to go smoothly at first, it soon runs into a few snags--the couple move next door to a suspicious prison guard who knows Arnie and, more importantly, Bill and his brother's wife begin to find themselves attracted to each other.