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There is no sex or nudity in the film. Some of the characters are seen in swimsuits but the context is not sexual - it's functional.
There is no violence or gore in the movie.
There is mild profanity in the film in 2 places. "What the h--l are you doing, Harker?" is the level and nature of the profanity.
There are two scenes of teen smoking and one of teen drinking. These are presented in the context of Alyssa being a troubled teen who later rights her course. These are the specific reason given by the MPAA for the PG-13 rating.
