Harry Potter and the Deathly Hallows

Following Dumbledore's death, Voldemort has completed his ascension to power and gains control of the Ministry of Magic. Harry, Ron, and Hermione drop out of school so that they can find and destroy Voldemort's remaining three Horcruxes. They isolate themselves to ensure the safety of their family and friends. They do not have much knowledge about the remaining Horcruxes except the possibility that two of them are objects that belonged to Hogwarts founders Rowena Ravenclaw and Helga Hufflepuff, and that the third is Nagini, Voldemort's snake familiar. The locations of the two founders' objects are unknown, and Nagini is presumed to be with Voldemort himself. As they search for the Horcruxes, the trio learn details about Dumbledore's past, as well as Snape's true motives.
The trio recovers the first of Voldemort's Horcruxes, Salazar Slytherin's locket, by infiltrating the Ministry of Magic. They recover the Sword of Godric Gryffindor; it is one of a few objects that can be used to destroy Horcruxes, and they use it to destroy the locket. In their travels the trio come across a strange symbol, which an eccentric wizard named Xenophilius Lovegood tells them represents the mythical Deathly Hallows. The Hallows are revealed to be three sacred objects: the Resurrection Stone, a stone with the power to bring others back to life; the Elder Wand, an unbeatable wand; and an infallible Invisibility Cloak. Harry learns that Voldemort is after the Elder Wand, but the trio decides that discovering Voldemort's Horcruxes is more important than procuring the wand for themselves. They break into Bellatrix Lestrange's vault at the Wizarding Bank Gringotts to recover another Horcrux, the cup of Helga Hufflepuff. Harry learns that another Horcrux is hidden in Hogwarts, and Harry, Ron, and Hermione enter the school. They find this Horcrux, the Diadem of Ravenclaw, and successfully destroy both.
The book culminates in the Battle of Hogwarts. Harry, Ron, and Hermione, in conjunction with students and members of the wizarding world opposed to the rise of Voldemort, defend Hogwarts from Voldemort, his Death Eaters, and various magical creatures. Several major characters are killed in the first wave of the battle. Harry discovers that Voldemort inadvertently made Harry a Horcrux when he attacked him as a baby, and that he would have to die in order to destroy Voldemort. Harry surrenders himself to Voldemort, who attacks Harry with the Killing Curse, sending Harry to a sort of Limbo between life and death. There, Harry meets Dumbledore who explains that because Voldemort used Harry's blood to regain his full strength, Harry is protected from any harm that Voldemort could commit, meaning that the Horcrux inside of Harry is destroyed but that he can return to his body despite being hit by the Killing Curse. Harry then returns to his body, the battle resumes, and after the last remaining Horcrux destroyed, Harry is able to defeat Voldemort.
The epilogue is set 19 years after Voldemort's death, involving Harry and Ginny, who are married, sending their sons, James and Albus, off to Hogwarts, with Ron and Hermione, who are now also married with children.