The Movies opens as Hermione and Harry simultaneously prepare to begin searching for and destroying Voldemort's Horcruxes. Meanwhile, Severus Snape arrives at Malfoy Manor and tells Voldemort when the Order will move Harry from Privet Drive. Voldemort borrows Lucius Malfoy's wand to avoid doing battle with twin wands and murders Charity Burbage, Professor of Muggle Studies at Hogwarts.
The Order arrives to meet Harry, and six others, which include Ron, Hermione, Fred and George Weasley, Fleur Delacour, and Mundungus Fletcher, to take Polyjuice Potion to become Harry's doppelgängers. Harry and the six copies leave Privet Drive paired with a protector, with the real Harry riding with Hagrid on his flying motorcycle. They are intercepted almost immediately by Death Eaters, and the pairs scatter. Voldemort appears, but Harry's wand defeats Voldemort's borrowed one and they arrive safely at the Burrow. All but Mad-Eye Moody, who was killed in the skirmish by Voldemort, and Mundungus, who disapparated when he saw Voldemort, arrive after, but George has a bad head wound from a curse Snape conjured. Ron convinces Harry to remain at the Burrow until after Bill and Fleur's wedding, before leaving to find and destroy the Horcruxes.
Minister of Magic Rufus Scrimgeour arrives at the Burrow and distributes the items from Dumbledore's last will and testament to Ron (the Deluminator), Hermione (personal copy of "The Tales of Beetle the Bard"), and Harry (the first Snitch Harry caught and the missing Sword of Gryffindor). During the wedding, Harry sees Xenophilius Lovegood and notices a strange symbol on his necklace. Harry talks to Elphias Dodge, one of Dumbledore's old friends, and Ron's Aunt Muriel, a gossiper, and learns that the Dumbledore family once lived in Harry's hometown, Godric's Hollow. A Patronus message sent by Kingsley Shacklebolt appears and warns that the Ministry has fallen, Scrimgeour is dead, and that "they are coming". Death Eaters appear, and Harry, Ron and Hermione disapparate to London.
Taking refuge in a cafe, they discuss their immediate plans, but before they can leave two Death Eaters arrive. The trio win the duel and escape to Grimmauld Place, where they discover that Regulus Arcturus Black, Sirius' younger brother, is the R.A.B. from the false locket found at the end of Half-Blood Prince. Kreacher reveals that the real locket was in the house, but Mundungus took it when he looted Grimmauld Place. Harry sends Kreacher to retrieve Mundungus, who explains that Umbridge extorted it from him in return for not revoking his peddler's license. They plan to break into the Ministry, now under the eye of Death Eaters, to recover it.
They capture and impersonate three Ministry members and enter, but are quickly split up: Hermione to the courtrooms with Umbridge to witness a false trial, Ron to the Head of Magical Law Enforcement's (Death Eater Yaxley's) office to deal with a lingering rainstorm charm, and Harry is left free to wander since he serendipitously copied the Death Eater Runcorn. Harry finds Umbridge's office, but not the locket, and makes his way down to courtroom, joined by Ron. They and Hermione stun Umbridge and take back the locket, and attempt to leave the Ministry. However, their Polyjuice Potion wears off, and during the battle to Floo away, Yaxley catches hold of them as they appear at Grimmauld Place.
Since they can no longer safely hide there with Yaxley now a Secret-Keeper, Hermione apparates them away to a forest. Ron gets splinched in the process, preventing the group from leaving their location until he recovers. They attempt to destroy the locket, but it proves indestructible to their magic, so they are forced to take turns wearing it despite its negative effect on their morale. While wearing it, Harry sees a vision of Voldemort interrogating and killing Gregorovitch the wand-maker, and going off in search of a mysterious teenage wizard that Gregorovitch said robbed his shop many years ago.
As they apparate around the countryside to camp in secluded places, Ron becomes increasingly suspicious that Harry and Hermione are becoming more than friends. While wearing the locket, he overhears Hermione discover that, if they can find the Sword of Gryffindor they can use it to destroy the Horcruxes. This realization that they must find yet another thing they don't know the location of, coupled with his increasing suspicion and resentment, drives him to leave the group and return home. Harry and Hermione are forced to teleport away, leaving Ron no way to return even if he wished to. Hermione takes his exit very badly, so Harry dances with her to a song on the radio to cheer her up--but the romantic situation is too much for Hermione, and she reverts to her sad mood.
Harry decides to visit Godric's Hollow, both to return there for the first time since Voldemort attacked him and to try and meet Bathilda Bagshot, a magical historian who "knew the Dumbledores better than anyone". They find the church graveyard, and Hermione discovers that a man named Ignotus Peverell's tombstone features the same symbol on Lovegood's necklace and in Dumbledore's book. Harry discovers his parent's gravestone, and an old woman approaches them while they pay their respects. Harry guesses that the woman is Bagshot, and they follow her to her home. Harry sees a picture of the teen from Gregorovitch's memory, and Bagshot takes him to the attic while Hermione wanders downstairs. She finds signs of a bloody attack, and realizes that the real Bagshot must be dead; the woman with Harry decomposes before his eyes into Voldemort's snake Nagini, and after a fight Harry and Hermione escape with the only casualty being Harry's wand. Hermione says that the teen from Gregorovitch's memory is Gellert Grindelwald.
In the forest where they spend the night, Harry sees a patronus doe while keeping watch, and follows it to a frozen pond. He discovers the Sword of Gryffindor at the bottom, but as he swims to reach it the locket goes berserk and attempts to drown him. Ron appears and saves him, grabbing the sword, and Harry convinces Ron to try and destroy the Horcrux. When Harry opens the locket using parseltongue, a monstrous black cloud erupts and shows Ron terrible visions--spiders, a ghostly Harry telling Ron that Mrs. Weasley wanted him for a son, and a ghostly Hermione mocking him and asking why she would choose Ron over The Chosen One, and the two forms begin kissing. Ron angrily attacks the locket with the sword, destroying the Horcrux, and the two return to the tent. Hermione is furious with Ron for leaving and returning like nothing happened, but the trio decide to visit Mr. Lovegood to find out about the symbol.
At the Lovegood house, Mr. Lovegood teaches them about the Deathly Hallows--an invincible Elder Wand, a Resurrecting Stone, and an Invisibility Cloak--and tells them the story of the three Peverell Brothers, who possessed the items. When the group attempts to leave, Mr. Lovegood reveals that the Death Eaters have taken Luna, and he must keep them there until they arrive to see his daughter again. They escape in the ensuing attack, but disapparate back to a former campground, where a group of Snatchers are waiting to capture them and take them to the Ministry. Hermione uses a Stinging Hex to disfigure Harry's face, but when the Snatchers see Harry's scar through the swelling they instead take the group to Malfoy Manor to collect a reward that was set for Harry.
Since the Malfoys and Bellatrix cannot be sure that the disfigured person is Harry, despite the fact that he is travelling with Ron and Hermione, they refrain from summoning Voldemort until the swelling dies down. However, Bellatrix sees the Sword of Gryffindor, which she believes resides in her vault at Gringott's Bank. She imprisons Harry and Ron in the cellar, where they find Luna, Ollivander, and a goblin; Bellatrix tortures Hermione to try to find out how they stole the sword. Wormtail takes the goblin upstairs to be interrogated, and Harry summons Dobby, who frees Luna and Ollivander before breaking Harry and Ron out. They go to rescue Hermione and the goblin, but despite winning the duels with Dobby's help, Bellatrix throws a knife that stabs and kills Dobby as they disapparate. Harry gives Dobby a proper burial on the beach where they appear.
The movie ends with Voldemort opening Dumbledore's tomb and taking the Elder Wand.
