The 1970s saw many disaster movies and this is one of the best of them.
The Poseidon is an elderly ocean liner on it's last trip across the Mediterranean when it is hit by a massive tidal wave. The ship is literally turned upside down. Preacher man Scott (Gene Hackman) takes charge of a group of survivors trapped in the ball room. He says that the only way out of the ship will be via the bowels of the ship, which are now above them!
With a motley collection of survivors including arrogant policeman Rogo (Ernest Borgnine), elderly couple Belle (Shelley Winters) and Manny (Jack Albertson) and teenager Susan (Pamela Sue Martin) and her annoying little brother Robin (Eric Shea), Scott leads his team through many dangers, not all of them surviving...
A well paced drama with just the right amount of human conflict to add to the series of dangers our heroes face. The set designs of the upside down ship are superb. An excellent film, any 1970s corniness cannot compete with the sheer adventure.