Mark and Elaine have two teenage kids, Ronnie and Stacey. And then there is Kate, Elaine's sister, who's been having an affair with Mark for fifteen years - she tells us in the opening voiceover. While living under the same roof, no less. She also tells us in that same voiceover that she's had some less-than-pure relations with Stacey over the years, but that's neither here nor there. Mark and Elaine are finished going at it, two things happen: first, he informs Elaine he taped them having sex. Second, he tells her he's leaving her. Brilliant. Kate rushes down to the boat, hoping they can go away together. When Mark refuses and wants to go alone, she hits him in the head with a champagne bottle, sending him overboard. When he doesn't surface, she decides to cover up the murder. The only problem is, the sexy new next-door neighbor, Vickie, saw someone else on the boat with Mark that night-though it was too dark to see who it was.