Plot

The wedding of Will Turner, a blacksmith-turned-pirate (Orlando Bloom) and Elizabeth Swann, daughter of Governor Swann (Keira Knightley) is disrupted by the arrival of Lord Cutler Beckett (Tom Hollander) of the East India Trading Company. Beckett has warrants to arrest them and ex-Commodore James Norrington (Jack Davenport) for helping Captain Jack Sparrow (Johnny Depp) evade his execution - a crime that carries the death penalty. Elizabeth is imprisoned while Beckett negotiates with Will: in exchange for their freedom, Will must locate Jack and retrieve his enchanted compass, which points in the direction of what a person most desires. Should Jack agree, Beckett will also offer him a Letter of Marque, granting him a full pardon and employing him as a privateer. Will expresses doubts that Jack will accept this offer, but agrees and sets sail.

At the same time, Jack Sparrow escapes from an unidentified prison and boards the Black Pearl with a drawing of a mysterious key. He convinces his disgruntled crew, bored of being chased by the Royal Navy on The Black Pearl and anxious to get back to pirating, that whatever the key unlocks is very valuable. Jack's confusion about what he wants, however, manifests in his compass spinning aimlessly, without a heading.

Later that night, Jack is visited by a reincarnated 'Bootstrap' Bill Turner (Stellan Skarsgard), Will's long-deceased father, and former Black Pearl crew member. He reveals he is now part of the crew of The Flying Dutchman, captained by Davy Jones (Bill Nighy). Bootstrap warns Jack that he must pay his debt to Jones (100 years of service), having asked him to raise the Pearl from the depths and make him captain for 13 years. Bootstrap further informs Jack that the Kraken will be sent after him if he is unable to repay, and Jack is marked for death by the 'Black Spot' appearing on his palm, a signal to the Kraken.

While searching for Jack, Will eventually finds the abandoned Black Pearl on Isla de Pelegostos. Jack, first mate Gibbs (Kevin McNally), and some surviving crew members are revealed to be in the custody of the cannibalistic Pelegosto tribe. The tribe has come to believe Jack is their God, and intends to kill and eat him to release him from his human form. Jack, Will and the crew eventually manage to escape the island. Will asks Jack for the compass, directing him to sail to Port Royal to secure Elizabeth's freedom, but Jack only agrees to help if Will helps him find the key. Jack steers the Black Pearl near the coastlines and away from the open ocean due to the fear of the Kraken.

Governor Swann uses his contacts to secure passage to England for Elizabeth, having no faith in Jack agreeing to return with Will. The plan is intercepted and thwarted at the Port Royal dock by Beckett's men, including his right-hand man Mr Mercer (David Schofield). In the scuffle, Elizabeth escapes and confronts Beckett, forcing him at gunpoint to sign and seal the Letter of Marque to take with her. Before she leaves, Beckett makes it clear that Elizabeth can choose to save either Will or Jack, as there is only one pardon, but he still expects her to bring him the compass. Elizabeth boards a ship in disguise as a stowaway to find Will.

Jack, Will and the crew pay a visit to voodoo priestess Tia Dalma (Naomie Harris), who finally tells them the significance of the key: it unlocks the Dead Man's Chest, where Davy Jones' heart lies. Jones was once a human being, but unable to bear the pain of love, he carved out his own heart, put it into his Chest and buried it in a secret location, carrying the key on his person at all times. He has now become a bizarre creature - part octopus, part crab, part man - and collects the souls of dead or dying sailors to serve aboard his ship for one hundred years. Tia also gives Jack a jar of dirt to protect him from Jones, as Jones is cursed to set foot on land only once every 10 years.

The Pearl comes across the Flying Dutchman, and Jack sends Will aboard to "settle" his debt with Jones. In reality, Jack hopes that Jones will accept Will's soul as payment in exchange for his own. Jones, incensed, refuses the offer and confronts Jack on the Black Pearl. Jack barters with Jones to discharge his debt if Jack can promise 100 souls to Jones in 3 days. Jack even agrees to leave Will behind as a goodwill gesture, leaving him with 99 more to procure. The Black Spot disappears from his hand.

On board the Dutchman, Will is reunited with his father. In an attempt to discern where Jones keeps the key, Will challenges Jones to a game of Liar's Dice, wagering a lifetime of servitude for the key. Jones is thus forced to show the key to Will before the game begins. Bootstrap suddenly enters the game and deliberately loses to prevent Will from losing, but Will reveals he just wanted to know where the key was kept. He later manages to steal the key from Jones while Jones is sleeping and escapes the ship, promising to return and rescue Bootstrap.

To find the 99 souls, Jack and his crew stop in Tortuga, where Elizabeth (in disguise) and a drunken Norrington join them. Norrington, fallen from grace, wants to kill Jack but is too drunk to even shoot straight. Since Jack's heart is muddled, he reckons that the compass in the hands of Elizabeth will give them a clear heading. He convinces her that finding the chest of Davy Jones is the quickest way to save Will, and the compass gives her a clear heading.

On board the Pearl, Elizabeth mentions that Will is working on Beckett's orders. Jack and Gibbs realize that Beckett wants the compass to seek the chest as well, hoping to use Jones' heart to control him and destroy piracy on the seas. Norrington picks up on the increasingly flirtatious banter between Elizabeth and Jack, which she dismisses as trust, and asks Elizabeth to think about how Will ended up on Jones's ship in the first place. It is suggested Elizabeth herself is confused by her feelings towards Jack, as the compass routinely points at him when she opens it.

Meanwhile, Will finds refuge on a trading ship, but it is destroyed by the Kraken when Davy Jones realizes he has escaped, forcing Bootstrap to watch. Will survives and hides on the mast of the Dutchman, while Jones decides to go after the chest and secure it, since it is no longer safe. Around this time, the Black Spot reappears on Jack's hand.

The Black Pearl sails to Isla Cruces, where the chest is buried, and Jack, Elizabeth, and Norrington recover it. Will suddenly arrives with the key. Quickly, the argument about the heart's fate flares tempers: Will is planning to stab the heart to free his father (unaware that whoever stabs the heart becomes the next captain of the Flying Dutchman); Norrington wants the heart to regain his position in the Navy; and Jack is primarily interested in becoming immortal, able to sail the ocean for all time. A three-way sword fight breaks out, in which Jack manages to make off with the key. While Pintel (Lee Arenberg) and Ragetti (Mackenzie Crook) try to steal the chest, Jones' crew arrives on the island, forcing Elizabeth, Pintel and Ragetti to fight them together, causing the chest to be dropped.

Jack finds and unlocks the chest. He retrieves the heart and hides it in the jar of dirt Tia Dalma gave him. Everyone reconvenes on the beach, where unbeknownst to all, Norrington spirits away the heart and the Letter of Marque. He makes a show of taking the chest to distract the Dutchman's crew and sprints away. Jack, believing the heart is still in the jar, rallies the rest of the crew to board the Pearl and sail away.

Later, the Flying Dutchman attacks the Black Pearl; in the chaos, the jar of dirt breaks, and Jack is horrified to realize the heart is not in it. The Pearl fends off the Dutchman, but Jones sets the Kraken after them shortly after. Jack takes the sole longboat to flee while the rest of the crew battle the Kraken, but he has a change of heart and eventually returns to help defeat the beast. They manage to wound it with an explosion, but the ship is heavily damaged and most of the crew are dead, leaving only Jack, Will, Elizabeth, Gibbs, Pintel, Ragetti, Cotton (David Bailie) and Marty (Martin Klebba). Knowing it will resurface shortly, Jack orders everyone to abandon ship. Elizabeth has put together that the Kraken is after Jack, not the ship or crew. She distracts Jack by kissing him, but chains him to the mast to ensure the rest of them have a chance. Unbeknownst to her, Will witnesses the kiss and is distraught. The crew make their escape.

Jack manages to free himself from the mast, but by this point, the Kraken has risen up behind him. In a final act of defiance, Jack launches himself into the Kraken's maw, and the monster takes the Pearl down to the depths. Jones watches from his telescope and proclaims that Jack's debt is settled. However, he then opens the chest to find the heart missing, to his fury. The heart and the Letter of Marque are delivered to Beckett by Norrington.

The surviving members of the Pearl return to Tia Dalma. Elizabeth is wracked with guilt at having killed Jack, prompting Tia to ask if they would be willing to retrieve Jack from Davy Jones' Locker. The crew enthusiastically agree. Tia muses that in order to do this, they will need a captain who knows those waters. Then, to everyone's surprise, a resurrected Captain Barbossa (Geoffrey Rush) appears, asking about the fate of his ship.