The novel starts with Harry witnessing, in a dream, the murder of a Muggle named Frank Bryce at the hands of Voldemort. He awakes with a searing pain in the lightning-bolt scar on his forehead. The next day the Weasleys take Harry and Hermione to the Quidditch World Cup using a magical teleportation object called a Portkey. There, Harry meets Cedric Diggory, who attends the game with his father, Amos. After the match, the Death Eaters, Voldemort’s followers, attack the site, causing havoc. The Dark Mark gets fired into the sky, which causes panic since it’s the first time it has been seen in over thirteen years. Winky, Barty Crouch Sr.’s house-elf, is blamed for casting the Mark after she is found holding Harry’s wand, which was used to cast the Mark.
The trio returns to Hogwarts, where ex-Auror Alastor “Mad-Eye” Moody will be teaching Defense Against the Dark Arts. Albus Dumbledore announces that Hogwarts will host the Triwizard Tournament, open only to students over the age of seventeen, and the prize for winning the tournament is one thousand gold Galleons. It will be the first time in two hundred years that the tournament has been held. Students from Beauxbatons Academy and Durmstrang Institute traveled to Hogwarts and stayed the entire year during the completion.
Students who hope to participate must place their names in the Goblet of Fire. On Halloween night, the Goblet picks Fleur Delacour, Viktor Krum, and Cedric Diggory, representing Beauxbatons, Durmstrang, and Hogwarts. The Goblet also gives a fourth name, Harry Potter, causing controversy and suspicion since Harry is underage. Ron refuses to speak to Harry because he is jealous that Harry is once again in the spotlight.
Hagrid tells Harry that the first task involves dragons and that Fleur and Viktor likely already know about it. Harry communicates the information to Cedric in order to keep a level playing field. For the first task, Harry has to pass a Hungarian Horntail to retrieve a golden egg, containing a hint about the next task. Harry succeeds by summoning his Firebolt broomstick with the Summoning Spell, and finishes the task tying for first place with Viktor. Ron reconciles with Harry after realizing the dangers of the Tournament. When Harry opens the egg, it shrieks loudly.
Meanwhile, a reporter named Rita Skeeter is writing scandalous articles and embellished rumors in the Daily Prophet about Hogwarts, Hermione, Harry, Hagrid, and the Headmistress of Beauxbatons.
The Yule Ball is approaching and Harry has to bring a date, so he approaches his crush Cho Chang, but she informs him that Cedric has already asked her. Harry eventually asks Parvati Patil and Ron takes her twin sister Padma. During the Yule Ball, Ron is shocked and jealous to see that Hermione attends the Ball with Viktor Krum. Cedric tells Harry that to open the egg, he needs to take it to the prefects’ bathroom. Harry ignores him due to his jealousy over Cho Chang.
However, as the challenge nears, Harry swallows his pride and takes the egg to the prefects’ bathroom, where Moaning Myrtle tells him that he needs to submerge it in order to understand the song. He realizes that the next task will take place underwater, so he begins looking for spells that would allow him to breathe underwater.
By the morning of the task, Harry hasn’t found a spell, but Dobby gives him Gillyweed, which gives Harry gills when he eats it. The third task takes place in the Black Lake and it involves saving the person each champion cares about the most. Underwater, Harry looks at Ron and Hermione, unsure which one he is supposed to pick. Viktor takes Hermione to the surface. He completes the task, finishing in third place, by rescuing Ron from under the lake and saving Gabrielle, Fleur’s sister. After the judges tally the votes they award him second place, giving him more points for saving Gabrielle.
One month before the final task, Harry and Krum are talking when they encounter Barty Crouch Sr., who looks to have gone insane, but tells Harry to get Dumbledore. Harry goes to look for Dumbledore, leaving Viktor with Barty. When they return they find Viktor stunned and Barty missing.
Harry prepares for the final task, a hedge maze. Inside the maze, Harry is forced to incapacitate Viktor, who has been bewitched with the Imperius curse and is torturing Cedric. Cedric and Harry both agree to win the Tournament together by grabbing the Cup at the same time. When they grab it they discover that it is a Portkey that transports them to a graveyard in Little Hangleton. There, Peter Pettigrew kills Cedric, and uses Harry’s blood, Tom Riddle Sr.’s bones, and his own arm to resurrect Lord Voldemort.
Voldemort summons his Death Eaters, berating them for thinking that he was dead. He then says that he only has one faithful servant at Hogwarts, who made sure that Harry would make it to the graveyard. He then challenges Harry to a duel. During the duel, Harry and Voldemort’s wands connect due to their identical cores. Voldemort’s wand releases the most recent spells it performed, resulting in the appearances of the ghosts of his victims, including Harry’s parents. Harry’s parents provide a distraction so he can escape back to Hogwarts using the Portkey, taking Cedric’s body with him.
When he returns, Mad-Eye Moody takes Harry to his office and reveals himself to be Voldemort’s servant. He admits to placing Harry’s name in the Goblet of Fire and helping him through the tournament, ensuring his win. Before Moody can kill Harry, Dumbledore, Professor McGonagall, and Severus Snape intervene. They learn that Moody is Barty Crouch Jr., disguised using Polyjuice Potion.
We learn that Crouch Jr. was sentenced to Azkaban by his father over his allegiance to the Dark Mark, but his parents later smuggled him out. Crouch Jr. is the one who stole Harry’s wand and cast the Dark Mark at the Quidditch World Cup in order to scare Voldemort’s former followers. Eventually, Voldemort got into contact with him and had him impersonate Moody. He also admits to killing his father to prevent him from telling Dumbledore about Voldemort. The real Alastor Moody is found inside Crouch Jr.’s enchanted trunk. Many people, including Cornelius Fudge, the Minister of Magic, do not believe Harry and Dumbledore about Voldemort’s return. Fudge allows a Dementor to perform the fatal Dementor’s Kiss on Crouch Jr. before he can testify about Voldemort's return. Hermione discovers that Rita Skeeter is an unregistered Animagus, who takes the form of a beetle, and she blackmails her in order to stop her from writing more smear pieces for The Daily Prophet.
Harry is declared the winner of the Triwizard Tournament and gives all his winnings to Fred and George to start their own joke shop. Harry returns home with the Dursleys.
