The fourth book starts with Harry's dream, where he sees Voldermort and Petter Pettigrew plotting to kill him. He then goes to the Quidditch World Cup with the Wesley Family and Hermonie. After the match, the Dark Mark appeared. The one caught at the scene was Winky, the Mr. Crouch's house elf.
When they return to Hogwarts, they found out that Hogwards will host the Triwizard Tournament. The Goblet of Fire chooses one student from each competing school. Students must be at least seventeen years old to enter this contest. Cedric Diggory is Hogwarts' champion, Fleur Delacour is Beauxbatons' and Viktor Krum represents Durmstrang. The Goblet unexpectedly selects a fourth champion, Harry Potter.
Harry is guided through the tournament by Moody. In the first task, the champions must retrieve a golden egg from a dragon. As part of the Triwizard Tournament's tradition, the students of Hogwarts, Durmstrang, and Beauxbatons remain at school to attend the Yule Ball.
The second task requires retrieving something important to each champion that is hidden in Hogwarts' lake. Harry uses gillyweed given by Dobby so he can breathe underwater. As the remainder of the school year passes, Harry regularly contacts his godfather, Sirius. One night, Harry and Krum are startled when Mr. Crouch emerges from the forest, demanding to see Dumbledore. Harry runs for help, but when he returns with Dumbledore, they find Krum unconscious and Crouch missing.
The third and final task involves navigating a large maze located on the Quidditch Pitch which is filled with magical obstacles. Harry and Cedric successfully navigate the maze, helping each other on the way. They reach the centre together, and grasp the prize to tie.The Cup, a portkey transports them to an old cemetery in Little Hangleton. Peter Pettigrew awaits them and kills Cedric.
Voldemort summons his Death Eaters by touching Pettigrew's Dark Mark. Voldemort challenges Harry to a duel. Harry manage to escape with Diggory's body and leaving Voldemort behind in a raging anger.
Moody then attempts to kill Harry himself, but Dumbledore arrived on time. Dumbledore had realized that something was wrong when he saw Moody whisk Harry away from the maze so quickly, and followed them. Dumbledore feeds Moody three drops of Veritaserum, a truth potion, and they discover that "Moody" is actually Barty Crouch Jr. Harry is taken to Dumbledore's office where he reunites with Sirius and he relives his story of his night.