Driving home from a wedding late one night during a heavy storm, out of cell range, Glen blows out his tires. He knocks on the door of the only house he sees and is greeted by an uncomfortably friendly middle-aged man, Arthur, and his attractive younger wife, Cyndi. The strange couple pours him a drink, and then more drinks, followed by odd confessions and an unexpected offer that Glen can't refuse. Where Ultrasound zigs and zags from there is into...