Andrzej and Krystyna, a well off couple, swerve to avoid a hitch-hiker in the road. Andrzej angrily ridicules the hitch-hiker but then chooses to pick him up when he thinks that's what Krystyna would do. They couple take him to their sailing boat and invite him on board.
On board, the hitch-hiker and Andrzej begin a game that sees them both trying to get one over on the other. When the hitch-hiker reveals a lock knife, the game is raised with neither able to escape because of their watery surroundings.
Knife In The Water is a very Roman Polanski film. Despite it being his first theatrical length film, it was clear that even during his late 20's, Polanski was already developing his trademark style - creating films with little relevance to the world but with a big impact.
Knife In The Water is similar to his later work Cul De Sac, in that they both show a seemingly happy couple that are pulled apart by an outside agent - in this case the hitch-hiker. In both films there is never an explosion of emotion, but more an acceptance of the fact that the external factor will be there for a while.
Halfway through the film, I began to realise that I was actually watching a film. Such is the skill of Polanski that you never appreciate the work that goes into it. The cameras flit from being on the sailing boat, to off the sailing boat with such ease. In fact, keeping the flow of the storyline when the cameras are so obviously placed in different positions is impressive to say the least.
Some people will feel robbed - and perhaps even disappointed - by the ending after the premise of the storyline (a clue is that the film is only rated PG), but the character study before this more than makes up for it.