This volume starts off with a description of some murders in the Riddle family house and how a man named Frank Bryce is accused of them.  He is later released for lack of evidence.  The Riddle house is abandoned and is beginning to fall apart when Frank investigates noises in the house.  He interrupts a meeting involving Voldemort and is killed.  Harry wakes up from a bad dream with his scar burning and he writes a letter to his godfather Sirius Black.  Over the summer Dudley has been put on a died so that he can fit into his school uniform.  Harry is invited by the Weasleys to stay with them for the rest of the summer and go to the World Quidditch Cup finals that are held in England this year.  After they get to the Burrow, Fred and George are scolded for their joke that they played on Dudley.  Harry and the Weasleys take a portkey and arrive at the World Cup site.  They make it to the Quidditch site and set up their tent.  When they get to their seats Harry meets Winky, the house elf of Barty Crouch.  Also there are the Malfoys and Obalonsk, Minister of Magic for Bulgaria.  Ireland wins even though Viktor Krum catches the snitch and Fred and George win their bet with Bagman which was that Ireland would win even though Krum would catch the snitch.  Some wizards, after the game, start to cause riots and the Ministry of Magic try to stop them.  Harry, Ron and Hermione go into the forest to keep out of site when they find Malfoy.  Harry loses his wand when they meet Bagman.  Suddenly the Dark Mark appears above them.  This is a mark made by Death Eaters when Voldemort was still around.  The Ministry of Magic arrive and stun Winky, the house elf, and it appears that he is the one that conjured the Dark Mark with Harry's wand. 

The group take the portkey back to the Burrow.  Mr Weasley tells of problems a reporter from the Daily Prophet named Rita Skeeter.  Mr Weasley must leave again to help correct problems that an ex-auror named "Mad-Eye" Moody creates by jinxing some dustbins.  Mrs Weasley takes everyone to the station and the kids are on their way back to Hogwart's.  Once at school, the first years students are sorted by the Sorting Hat.  "Mad Eye" Moody is introduced as the new Defense Against the Dark Arts teacher and then Professor Dumbledore announces that a Triwizard Tournament will be held at Hogwart's.  The first in over 100 years.  Fred and George try to enter even though they fall below the age limit.  Hermione finds that Hogwarts employs house elves.

The students learn from Professor Moody in Defense Against the Dark Arts about the unforgivable curses.  Hermione starts SPEW to help liberate house elves.  Harry gets a letter from Sirius Black which tells him that he is coming back to visit.  Harry sends an owl to Sirius letting him know that everything is okay.  Professor Moody teaches the Impervious curse in Defense Against the Dark Arts and everyone succumbs except for Harry who resists it after a while.  Hedwig delivers a letter that says that Sirius is back in the country.  The two other schools that are competing in the tournament arrive: Beauxbaton and Durmstrang. 

Everyone gathers in the Great Hall where all three schools learn about the Triwizard Tournament.  Fred and George are unable to get their names into the goblet.  After dinner on Halloween, the Goblet of Fire chooses the champions.  They are Viktor Krum of Durmstrang, Fleur Delacour of Beauxbatons and Cedric Diggory of Howarts.  Although there were only supposed to be three champions, Harry Potter is chosen as the fourth and holding to the rules of the tournament, he must compete if chosen.  No one believes that Harry did not enter himself.  Everyone is disappointed in Harry for, what they think, is cheating with the Goblet of Fire.  Harry is excused from Potions for the weighing of the wands and then later he gets an owl from Sirius asking for Harry to meet him.

An article by Rita Skeeter insinuates that Harry and Hermione are a item and Hermione tries to get Harry and Ron to make up.  Ron and Harry had been bickering since Ron thinks Harry cheated also.  Hagrid asks Harry to meet him that night and he shows him the dragons that are the first task of the tournament.  Harry and Hermione try to find spells that they can use against dragons to no avail.  Harry, as a courtesy, warns Cedric about the dragons and Professor Moody gives Harry a hint on how to get by the dragon.  Because of this hint, Hermione helps Harry to learn a summoning charm.  The first task is to get a golden egg that is protected by a dragon.  Each student succeeds at this but Harry finishes in the shortest amount of time.  Mr Bagman tells the students that the clue to their next task is inside the eggs and that each must learn to open the eggs themselves.  Rita Skeeter shows up to get an interview with Hagrid.

Harry discovers that he is expected to have a date to the Yule Ball.  He wants to ask Cho but by the time her works up the nerve, she has already said yes to Cedric.  He asks Parvati Patil instead.

Rita Skeeter writes an article about Hagrid being half giant he sulks in his cabin.  A substitute takes his place in Care of Magical Creatures.  At Hogsmeade Harry meets Bagman who offers to help Harry. 

Harry finally learns how to open his egg with a hint from Cedric, who repays Harry earlier warning about the dragons, and help from Moaning Myrtle.  Harry sees Mr Crouch on the Marauder's Map in Professor Snape's office and goes to see what is going on.  Professor Snape, Professor Moody and Mr Filch meet him on the stairs but they do not see him.  Professor Snape and Mr Filch leave by Moody, who can see him under the cloak borrows Harry's map.

Hagrid goes back to teaching Care of Magical Creatures and the second task is set.  Harry cannot find a spell that will help him and finally Dobby gives him Gillyweed so that he can breath underwater.  The task is to recover from the merpeople in the lake what was taken from them.  This end up being someone dear to each of the contestants.  Harry rescues Ron and goes back for Fleur's sister, not realizing that she is in no real danger.  He ends up tying with Viktor Krum because of the delay in going back.

Harry, Ron and Hermione meet Sirius Black outside Hogsmeade and learn about Barty Crouch's son dying in Azkaban.  His son was tried and convicted of being a servant of Voldemort but always maintained his innocence.  Harry soon learns that the third task is a maze.  Mr Crouch shows up wounded and mumbling and Harry runs to get Professor Dumbledore.  Before he can get back, though, Mr Crouch attacks Viktor Krum and leaves.

Harry dreams of Voldemort in divination class and goes to tell Professor Dumbledore about it.  Harry, being left alone in Professor Dumbledore's office, looks into the Pensieve, a device he found in the office.  He witnesses Karkaroff giving testimony in court against Crouch's son who is then sentenced to serve time in Azkaban Prison.  Harry eventually tells Dumbledore about his dream.  Harry practices spells for the Third Task while Rita Skeeter writes another article about Harry.  Hermione discovers the truth about Rita Skeeter.  The champions enter the maze and start to battle/overcome the various monsters.  Harry meets a Sphinx and solves its riddle but is attacked by a large spider.  Harry and Cedric meet up and it appears that they are the first to the cup.  They agree that it is only sporting that they both take the cup at the same time.  When they both touch the cup, it turns out to be a portkey and Harry and Cedric are sent to a dark graveyard.  Here they find Voldemort as a horrible deformed baby looking thing.  Cedric is killed by the Avada Kadavra curse and Harry is tied to a tombstone while Wormtail resurrects Voldemort using Harry's blood and his own hand.  After Voldemort regains his form, he calls the Death Eaters.  Voldemort tries to kill Harry again but their spells somehow form together.  This causes Voldemort's wand to reveal the last few people that he killed and, with his "father's" help, Harry escapes through the portkey.

Harry appears in the maze once again and tells "Mad Eye" Moody what happened.  Moody tells Harry that he was the Death Eater at Hogwarts and that he entered Harry's name into the Goblet of Fire.  When Moody tries to kill Harry, Professors Dumbledore, McGonagall and Snape arrive to help.  Professor Dumbledore stuns Moody and then opens a trunk in Moody's office to reveal the real "Mad Eye" Moody in a pit.  Eventually the Polyjuice Potion that he was wearing wears off the imposter and he is shown to be Crouch's son.  With veritaserum they get him to tell them of Voldemort's plans.  Harry lets Professor Dumbledore and Sirius Black know what happened to him and Cedric and then they send him to the hospital wing.  The Minister of Magic, Mr Fudge, shows up with a dementor that kills Crouch's son.  He doesn't believe Professor Dumbledore when told that Voldemort is back. 

Professor Dumbledore tells the students about Cedric's death.  He also tells them the truth about Voldemort's return.  On the way home, Hermione shows Ron and Harry that she captured Rita Skeeter.  She is an unregistered animagus, a beetle, and she has her in a jar.  Harry can't seem to accept the award money because of Cedric's death.  He instead gives it to Fred and George Weasley so that they can start the joke shop they've always wanted to.