The book starts off at the Riddle House, Little Hangleton and we learn of how a man called Frank was wrongly accused of killing the Riddles many years ago. We also learn that Harry has dreamt of Voldemort killing Frank at the Riddle House with Wormtail (Peter Pettigrew, Scabbers) at his side and has woken up with his scar hurting. He writes and tells Sirius.

Dudley is on a diet and Aunt Petunia thinks that everyone else should be. Harry agrees to their surprise, but they're unaware that he's been sent food. The Dursleys are also scared of Sirius, which Harry is using to his advantage.

He gets invited to the Quidditch World Cup with Ron and the rest of the Weasley's, Hermione included of course and using sneaky tactics, Uncle Vernon agrees. The Weasley's don't pick him up by car though they come by Floo to everyone's surprise and knock the Dursley's fireplace out. The twins drop a sweet and Dudley greedily eats it causing his tongue to grow. Mr Weasley makes them all go back, while he sorts out the damage. The twins get told off back at home and Mrs Weasley rips up their order forms and confiscates the trick sweets. Harry meets Bill and Charlie for the first time and is surprised how "cool" Bill is.

After the match, Ireland is celebrating and someone conjures up the Dark Mark. The Dark Mark is the signal of Voldemort's death eaters, so panic is raised and Mr Weasley directs everyone to go into the woods for safety. Harry realises that he has lost his wand before he came into the woods and panics. Winky is caught with it and they find out it was Harry's wand that was used to conjure the Dark Mark. Barty Crouch (her master) fires Winky and she is unhappy.

When they return home the next day, Mrs Weasley is worried and forgives Fred and George for making the joke sweets. Mr Weasley is called into work urgently with a problem with a person called Mad-eye Moody, so can't see them off to Hogwarts.

School settles in and the Beauxbatons and Durmstrang students arrive including Viktor Krum who is still at school at Durmstrang. The night comes for the Goblet of Fire to choose the champions and it chooses Cedric Diggory (Hufflepuff, prefect, seeker and Captain of Quidditch), Fleur Delacour (Beauxbatons, part Veela), Viktor Krum (Durmstrang, international Quidditch player) and then the Goblet spits out one more name than it should, Harry Potter. Everyone is shocked, including Harry but he has to compete as it is a magical contract your name been in the Goblet of Fire.

Hermione sets up a campaign called SPEW to stop the cruel treatment of house-elves but nobody is interested. Harry finds out that the first task is dragons but he only has Hermione to help him as he's fallen out with Ron. Sirius is concerned about Harry and returns to England. He meets him one night but the meeting is cut short when Ron walks in and Sirius has to disappear.

Ron and Harry are now friends and Harry meets an old friend at Hogwarts, Dobby. In Defence Against the Dark Arts they learn of the three curses that will give you a life-sentence term in Azkaban if used.

Harry tries to figure out the second task and gets a hint from Diggory. He tries out his advice and Myrtle shows up, teasing him. He sneaks back to the dorm but drops the egg and Marauder's Map and gets his leg stuck. Filch shows up, thinking it's Peeves, then Snape and then Moody. Moody can see Harry because of his magical eye and realises that the egg and map is his. He asks to keep the map once Snape and Filch are gone.

Dobby steals some Gillyweed to give to Harry for the second task and realises that he has to rescue Ron from the Mer-people in the lake. He ends up going over the time limit though to make sure that everyone is rescued. Diggory and Harry are now drawing on points.

Hagrid is convinced to come back and returns. Ron admits how much he hates been poor. Ron, Hermione and Harry visit Sirius outside Hogsmeade and fetch him food. Ron and Hermione are not speaking though now. An article appears saying that Harry and Hermione are going out but she's also going out with Viktor Krum who has invited her to visit him in the summer and they are puzzled about where she's getting the information from as she's not allowed in the Hogwarts grounds. Hermione receives hate mail because of it.

Mr Crouch, one of the organisers of the Tournament stops coming to Hogwarts to judge and Percy takes over the position claiming that Crouch is not well. Crouch turns up at Hogwarts and begs Harry to get Dumbledore when Harry is talking to Viktor and Harry rushes off. Viktor is laid out on the floor when Harry comes back and Crouch is gone.

Harry learns that Snape, Karkaroff and Bagman were all charged with been Voldemort's Death Eaters but they all got off. Crouch was not lenient with his son though and had him sentenced to Azkaban.

The Third Task comes and the whole school is excited. Ron and Hermione have been helping Harry to get through the maze to reach the middle of it where the Tri-Wizard Tournament Cup will be. He has to get past the creature obstacles. Mrs Weasley and Bill come to watch him and Diggory and Harry get a time advantage, as they had the most points. In the maze though things start to go wrong. Fleur is attacked and is taken out of the maze, Krum is jinxed and made to try and kill Diggory. Harry stops him in time and there is only Diggory and Harry left. They decide to take the Cup together to have the glory for Hogwarts, not for themselves. They don't realise that the Cup is a Portkey and it transports them to The Riddle House.

Diggory is killed instantaneously by the Avada Kedavra curse and Harry is tied up by Wormtail and his wand taken off him. He watches a spell been performed, Harry's blood is needed for it and Voldemort returns to his old body, he is alive once more. Voldemort calls the Death Eaters, who reassemble around their master. This includes Lucius Malfoy. Harry learns that Voldemort will duel with him to death as he is untied and given his wand back. He tries to run and hide but then decides he will die like his parents.

They both shout a spell at the same time and something strange happens. A thread connects their wands and they rise in the air. Diggory appears out of Voldemort's wand and asks Harry to take his body to his parent's. Frank then appears, encouraging Harry to keep the thread, then Bertha Jorkins and then his parents. His father explains what he has to do and Harry breaks the connection and runs with Cedric's body for the Portkey.

Harry arrives back at Hogwarts and people surround him and he tries to explain about Diggory. Moody takes him to his office and we find out, it's not Moody but Barty Crouch Jr who was rescued from Azkaban and has been taken the Polyjuice Potion to be Moody. He explains how he is a Death Eater and how he's going to take Harry back to Voldemort. Dumbledore bursts in with Snape and McGonagall and Harry is saved. They place the truth potion on Barty and he explains everything.

Harry is taken to Dumbledore's office where Sirius is and has to explain everything. He's then made to go to the hospital wing to relax and rest with Sirius remaining with him.

Fudge shows up with a Dementor and administers the kiss on Crouch, meaning that their proof of Voldemort returning is gone. Dumbledore is not pleased and they part ways. Sirius and Snape are made to make "friends" as Dumbledore explains that they have to all work together to stop Voldemort. Mrs Weasley is shocked that she is in the same room as a "murderer." Hagrid is asked along with Madam Maxime to do a task for Dumbledore this summer.

At the leaving feast, Dumbledore explains how Cedric Diggory was murdered and the school is shocked. He also explains about Voldemort. He issues an invitation to their foreign guests that they are always welcome at Hogwarts. The real Mad-eye Moody is also at the feast. Dumbledore explains to Harry that Voldemort and Harry's wand both contain a feather from Fawkes and that's why the thread happened. He also explains that they will all have to fight hard to stop Voldemort.

On the train home, Hermione explains why Rita Skeeter hasn't written any articles. She's an illegal Animagus and Hermione has trapped in her jar until she promises not to write untrue stories. Harry gives the 1000 galleon prize-money from the Tri-Wizard Tournament to the twins to start up their joke shop. They are amazed. Harry leaves Kings Cross, trying to think positively about the events to come.