Dark Harbor (1998)

A bickering couple speed through a downpour, trying to catch the last ferry to their island retreat. Suddenly, they spot a crumpled body lying at the side of the road. After much argument, the couple stop to aid the battered and bruised young man. Their offer of summoning the police firmly rejected, the couple help the young man as best they can - although it certainly means missing their ferry. - This begins a tale of twisted sexual attraction and ulterior motives.