The summaries below give a brief overview of the chapters after The Second Task and all the way to the end of the book, involving the Third Task and Harry's battle with Voldemort, as well as the Minister of Magic refusing to believe Harry's story about how Voldemort returning to power.
In Chapter 27, Harry, Ron, and Hermione meet Sirius, Harry’s godfather, on their trip to Hogsmeade and talk privately inside a concealed cave. Sirius gives them new information about Mr. Crouch and how his son was caught with supporters of Voldemort trying to find him. This comes in useful later, as it helps explain Mr. Crouch’s backstory. In Chapter 28, Harry and the rest of the champions learn about the third task – finding the Triwizard Cup in the middle of a huge maze full of a variety of dangerous obstacles to win the entire Triwizard Tournament. After Harry learns about this, Mr. Crouch strangely turns up by the edge of the forest when Krum and Harry are alone, acting insane, claiming Voldemort is getting stronger, and demanding for Dumbledore. However, when Harry arrives with Dumbledore again, Krum is attacked by Mr. Crouch, who even more strangely disappears shortly after. In Chapter 29, Harry has another weird, vivid dream about Voldemort during class and awakes with his scar hurting… just like the one he had before school had started. This time, he decides to tell Dumbledore about it and goes to his office.
In Chapter 30, Harry finds a strange, glowing basin in Dumbledore’s office while by himself and accidentally transports himself into one of Dumbledore’s memories from a long time ago– the trials that Dumbledore attended. Harry sees three of them: one where Karkaroff was brought from prison to give information to the ministry about Death Eaters (supporters of Voldemort); another where Ludo Bagman was accused of passing information to Death Eaters, and the final where Mr. Crouch’s son was brought to Azkaban (the wizarding prison) for being caught with Death Eaters. After being brought back to Dumbledore’s office, he tells him about the dream he had. Dumbledore then shares his theories on why Harry keeps having dreams and why his scar is hurting. In Chapter 31, Harry makes his way through the Third Task, ending up touching the Triwizard Cup at exactly the same time as Cedric. Strangely, the cup is a portkey and they are both whisked away to some unknown place…
In Chapter 32, Harry and Cedric are transported to a graveyard. Cedric is sadly killed by Wormtail, who was helping Voldemort return to power. By completing an advanced potion that requires Harry’s blood, Wormtail then helps Voldemort rise to power again. In Chapter 33, Voldemort is quickly surrounded by many of his past supporters (the Death Eaters), who can’t believe their eyes that their master is back after all these years… Voldemort explains to the Death Eaters how he came back to life, saying that the only reason that Harry had been able to stay alive almost fourteen years ago was only because of his mother’s love… how Harry and Dumbledore weren’t powerful at all, and that luck had simply played their way… and how now, Voldemort would finally be able to get rid of Harry.
In Chapter 34, Voldemort and Harry duel in the graveyard amongst the Death Eaters. However, a very strange thing happens when Voldemort tries to use the Killing Curse on Harry… when Harry casts the Disarming spell at the same time, the two spells join together, neither of them taking effect… then ghosts of past spells of Voldemort’s wand come out, of many of the people he had killed before, who talk to Harry and help him escape Voldemort. Harry manages to use the Triwizard Cup to travel back to Hogwarts and very narrowly escape Voldemort. In Chapter 35, Harry returns to utter confusion and fear by everyone else. Professor Moody then forces him to his office, where he reveals that it was he who put Harry’s name in the Goblet of Fire… him who made sure that Harry made his way successfully through the tournament so he could be tricked into taking the portkey to Voldemort. Just as Moody is about to curse Harry, Dumbledore arrives and stops him and tells Harry that Moody was Mr. Crouch’s son, whom many believed had died years ago in Azkaban. Dumbledore then forces Moody to tell the truth about his past with Veritaserum, revealing how his mother saved him from dying in Askaban, how he had been under the Imperius curse, and how Voldemort came to him asking for his help.
In Chapter 36, Harry tells Sirius and Dumbledore exactly what happened with Voldemort before going to the Hospital Wing. Soon he awakes and learns that a Dementor had performed the Kiss on Mr. Crouch’s son, the Moody imposter, meaning that his soul was sucked out. The minister of magic, Cornelius Fudge, then refuses to believe that Voldemort has come back, starting the parting of ways; Dumbledore and Fudge act as they both see fit, Dumbledore preparing for the attacks from Voldemort and Fudge acting normally, as he believes that it would hurt his reputation too badly if he were to tell the world about Voldemort’s return. In Chapter 37, Dumbledore addresses the entire school about the incident between Harry and Voldemort and tells everyone the truth. Harry then takes the Hogwarts Express home, in which Hermione reveals that Rita Skeeter turned into a beetle to spy on people and gain information for the daily prophet. Harry travels with the Dursleys back to their house, concluding the book.