By Catholic News Service

A solitary medical student (Blake Lively) is pursued by a great white shark near a secluded Mexican beach and is forced to improvise to save her life.

Director Jaume Collet-Serra and screenwriter Anthony Jaswinski at times appear to struggle with sustaining tension while giving their heroine unexpected tasks.

Some gore, fleeting rough and crude language. The Catholic News Service classification is A-III — adults. The Motion Picture Association of America rating, PG-13 — parents strongly cautioned. Some material may be inappropriate for children under 13.