Just after midnight on New Year's Eve, the luxury liner SS Poseidon is hit by a 150-foot rogue wave. Most of the passengers are trapped and drowned when the ship overturns, but a small band of survivors, loosely led by professional gambler Dylan Johns (Josh Lucas), struggle to make their way to the hull before the ship sinks.

Poseidon is a loose remake of The Poseidon Adventure (1972) (1972), both of which were based on The Poseidon Adventure (1969), a novel by American writer Paul Gallico. Gallico based The Poseidon Adventure on an incident regarding the British ocean liner RMS Queen Mary, which almost capsized after being hit by a 90-foot rogue wave in 1942. The screenplay for Poseidon was written by American screenwriter Mark Protosevich.

Rogue waves (also known as freak waves, monster waves, killer waves, extreme waves, abnormal waves, and tsunamis) are relatively large and spontaneous ocean surface waves that occur far out at sea, typically as a result of earthquakes under the sea, high winds, and strong currents.

The small group of survivors who band together with Dylan Johns in hopes of finding a way out of the upside-down ship include former New York mayor Robert Ramsey (Kurt Russell), his daughter Jennifer (Emmy Rossum), Jennifer's fiancé Christian (Mike Vogel), single mother Maggie James (Jacinda Barrett) and her young son Conor (Jimmy Bennett), stowaway Elena Morales (Mía Maestro), gay architect Richard Nelson (Richard Dreyfuss), waiter Marco Valentin (Freddy Rodríguez), and drunken card-player Lucky Larry (Kevin Dillon).

Director Wolfgang Petersen and the film-making crew did not have access to a real cruise ship because they were only upright for 20 minutes at the beginning of the movie. After that, the ship was upside down. Because they needed the opening scene in which Dylan is seen running on the deck, they had Lucas run against a green screen and then placed him on a CGI-created cruise liner.

In The Poseidon Adventure, the cruise liner was in route from New York City to Athens. They were sailing on the Mediterranean Sea. In the remake, it is never specified as to where the SS Poseidon was going, so the name of the ocean on which they were traveling was not announced, although there are some clues. Elena tells Nelson that she hooked up with Valentin because she had no money and no other way to get to her sick brother in New York, so it seems likely that New York is the ship's destination. Nelson mentions early in the film that he has just left his lover behind in London, having told his business associates that the lover "missed the boat" because of a supposed emergency at work. At a few points in the movie, the word "Southampton", a port on the South coast of England, can be seen on the ship, so it seems most likely that this particular Poseidon was sailing from London to New York via the North Atlantic Ocean.

No and yes. The poker dealer is heard saying "15 to call...30 to call" and, according to poker rules, as soon as the player states "call", they normally are not allowed to raise. However, Robert and Dylan continue to place in more chips, making an against-the-rules move known as a "string bet". However, cruise ships and small poker businesses that are not professional could, in-fact, change the rules to some extent.

While everyone was focused on cheering in the New Year, Chief Officer Reynolds (Kirk B.R. Woller) felt something odd, either in the vibration or hum of the ship's engines, the movement of the ocean's currents, or just the feel of the night air, hence his comment, 'Something's off.' Looking through his binoculars, he spies the rogue wave heading toward them and immediately orders that the ship be turned 'hard to starboard' (hard to the right). Unfortunately, there isn't enough time before the massive wave is upon them.

Richard's boyfriend left him for another man and did not call him at midnight like Richard had begged him to do. Suffering from a broken heart, Richard goes out on the deck and is about to toss himself overboard when the rogue wave hits.

The reason everyone was electrocuted was because the sprinklers turned on, dumping water on the floor and making contact with the numerous broken wires and lights. Electricity is carried by metal and water, so Lucky Larry must have been lying in a dry spot with no metal objects touching him or he could have been standing on something nonmetallic that lifted him above the water. That's why he's called "Lucky" Larry.

Dylan Johns was once in the Navy, evidenced when Robert asks him whether he toured on a sub and Dylan replies: "Wouldn't call it touring." He obviously has a working knowledge of how a ship operates. With regards to the layout of the Poseidon, he locates various schematics of the ship as they move about from level to level.

The Poseidon has numerous ballast tanks which can be filled with seawater to give some heaviness to the ship's bottom and make her more stable.The tanks are set to fill from tank 1 to tank 2 to tank 3 and so forth. When the survivors enter the first ballast tank, they find it empty and sealed by a pressure valve that can only be opened when the tank is full of water. The plan is to flood that tank until the hatch opens and then let the water carry them into the second empty tank and so on until they find a tank where the valve is already open. When they are carried into the second ballast tank, however, there is already water in it and the hatch is open. The water already in the second tank came from a flooded corridor through which Dylan swims until he finds a stairwell leading up to a higher level not flooded. In fact, it's lucky for them that tank 2 was already holding water or they might have been injured when they came barreling through and hit the tank's ceiling.

Earlier in the movie, Nelson discovered that all bets were off with his ex-boyfriend. When he met Elena, he seemed to form a relationship with her. It is conceivable that he might have been bi-sexual, but not all relationships involve a sexual component, such as those formed under danger or duress. In the short time they spend together, we never see Nelson offer Elena anything other than kindness and comforting, so most viewers conclude that the nature of their "relationship" is one of emotional comfort in shared adversity.

Although the turn-off button for the propeller blades is broken, Robert manages to reverse the spin of the propellers in the bow thrusters, creating suction instead of blasting the propeller room with air. Fighting to keep himself from getting sucked into the blades, Dylan tosses in a large air tank that immediately explodes, knocking out one of the propellers. As water begins leaking in all around the engine room, the survivors exit the ship through the propeller shaft and leap into the ocean. They swim to an inflatable life raft and climb in just as the Poseidon rights itself and slips into the depths, stern first. In the final scene, Dylan finds a flare gun in the raft and fires it. Shortly thereafter, they are noticed by two rescue helicopters who converge their searchlights on the raft, forming a perfect V against the dark water.

Of the ten main characters, six survive and four die. Valentin is crushed by a falling elevator, Lucky Larry is crushed by a falling engine, Elena hits her head on a cement block and drowns, and Robert drowns while attempting to turn off the spinning propellers in the submerged engine room. Those who did not follow Dylan are all killed, either by drowning (e.g., Captain Bradford (Andre Braugher), Gloria the Entertainer (Fergie), and Chief Officer Reynolds), by electrocution, or by fire.

All ships have to have inflatable life rafts in case the lifeboats can't be used, like if the ship is listing to one side, which would make half of the lifeboats unusable. The red cabinets you see on the deck as Dylan is jogging contain the rafts. As the ship is going down, they will automatically blow open and float to the water's surface. The reason it was still sitting near the ship and hadn't drifted away is because they're tethered to the ship, set up with a breakable link so that when the ship goes under and a certain amount of force is put on the link, it will snap free so the sinking vessel doesn't pull the raft down with it. In short, the life raft did exactly what it's supposed to do in real life, and it's not an impossible scenario at all for it to have been sitting there waiting for them. That's the whole point to the things!

Following the wave hitting the ship, a GPS locator beacon was launched to alert the Coast Guard. The signal alerted them of the Poseidon's position.

There are actually three scenes that were in the theatrical trailer that did not come up in the 2006 theatrical release. There is a scene involving Christian and Jennifer Ramsey in the night club on New Years Eve regarding her fear of telling her father about their engagement. Another scene is an extended poker scene involving Robert Ramsey, Lucky Larry, and Dylan Johns. The final scene involves Captain Michael Bradford telling the panicked ballroom survivors that they are the lucky ones.