Thirteen years after the battle of Calypso's maelstrom, a twelve-year-old Henry Turner boards the Flying Dutchman and informs his father, Will, that the curse which binds Will to the Dutchman and only permits him to step on land once a decade can be broken by the Trident of Poseidon. Henry intends to recruit Captain Jack Sparrow to help find it, but Will believes this is impossible and orders Henry to leave. Will and the Dutchman then disappear into the sea, but Henry vows to find Jack and the Trident.
Nine years later, Henry is a sailor in the Royal Navy. The ship sails into the supernatural Devil's Triangle and stumbles upon the wreck of the Silent Mary, whose ghostly crew led by Spanish pirate-hunter, Captain Armando Salazar, attacks, sparing Henry's life so that he can deliver a message to Jack, who killed Salazar and his crew decades ago by leading them to the Devil’s Triangle and inadvertently cursed them.
In Saint Martin, a young astronomer named Carina Smyth is sentenced to death for witchcraft but escapes and crosses paths with Jack as he and his crew blunder a bank robbery. Jack trades his compass for a drink, and the betrayal of the compass frees Salazar and his crew from the Devil's Triangle. Carina learns Henry is looking for the Trident's resting place and offers to help him using her unknown father's diary. Carina and Jack stall the execution process, but they escape with the help of Henry and Jack's crew, setting sail on the Dying Gull. Carina deciphers the clues in her diary, discovering that the stars will lead to an island where the Trident is hidden.
Meanwhile, Captain Hector Barbossa hears from his pirate crew that the revived Captain Salazar has killed several pirates at sea and is destroying Barbossa's fleet. Barbossa talks his way out of being killed by offering to help find Jack and learns that the Trident could lead him to a "treasure". Salazar agrees, wanting revenge on Jack. Salazar pursues the Dying Gull, forcing Jack, Henry, and Carina to flee to an island, discovering that Salazar's crew cannot go on land. Barbossa allies himself with Jack, returning his compass and restoring the miniaturized Black Pearl, to its original size. They continue their journey to the island, with Barbossa taking command of the Pearl once more. During the voyage, Jack and Barbossa realize Carina is the latter's long-lost daughter.
The Pearl approaches the Trident's island and evades a Royal Navy warship until it is destroyed by the Silent Mary before the Pearl runs aground on the island. Jack, Barbossa, and Carina use the island's magic to part the ocean and open a path to the Trident on the ocean floor. Salazar captures Henry and possesses him to walk on the ocean floor and seize the Trident. Once he does so, Henry is given his body back, and Jack distracts Salazar, allowing Henry to destroy the Trident, breaking all curses upon the sea and restoring Salazar's crew to life. However, the divided sea begins to collapse in on itself. The Pearl lowers its anchor to lift the group to safety, but Salazar pursues them, still hell-bent on killing Jack. Carina realizes that Barbossa is her father when she spots a tattoo on his arm identical to the diary's cover. Barbossa sacrifices himself to kill Salazar, allowing the others to escape.
Sometime later, Henry and Carina reach Port Royal, where Will appears, free from the Dutchman. His wife, Elizabeth Swann, appears moments later and the Turner family reunites. Henry and Carina kiss. Jack watches from the Pearl before sailing away into the horizon, captain once again, while also adopting Captain Barbossa's monkey.
In a post-credits scene, Will and Elizabeth are asleep in their bed, when Davy Jones appears in their room. Assuming he had a nightmare, Will goes back to sleep, oblivious to the wet barnacles on the floor.
