Using his middle name, Marvolo , which was taken from his maternal grandfather, Riddle discovered his mother's heritage and the Gaunts' bloodline connection with Salazar Slytherin. Once Tom learned of his ancestry, it was not long before he discovered the existence of the Chamber of Secrets under Hogwarts, during his fifth year, and tamed the Basilisk which dwelt within. As the Heir of Slytherin through his mother's family, Tom was able to open the Chamber Slytherin had left behind in order to " purge the school of all those who [were] unworthy to study magic " — in Tom's and Slytherin's eyes, Muggle-borns . 
It was a completely ordinary day at Hogwarts. The headmaster was counting lemon drops in an attempt to stretch his supply – he had had to limit his exorbitant sweets budget in order to acquire the necessary funds for a dangerous international tournament. A tearful Draco Malfoy was writing an angry letter to his father regarding an impromptu demonstration of the human-to-ferret transfiguration carried out by the defense professor. Meanwhile, said defense professor was busy stealing polyjuice potion to hide that he was, in fact, not very concerned with defending against the dark arts. In the library, a boy with a lightning bolt scar and a girl with bushy hair were researching methods to keep the boy from getting eaten by a dragon. It was an ordinary day, that is, until the boy explained a plan suggested by the defense professor.
The morning of the third task, Rita Skeeter prints an article about how Harry fainted in class and is possibly disturbed. The evening of the task, the four champions enter the maze, and Harry finds his path relatively manageable. Soon both Fleur and Krum are out of the running, and Harry and Cedric, the only remaining contestants, arrive at the trophy at the same time, and they both agree to touch it together. The trophy turns out to be a portkey, and it takes both boys to a far away graveyard, where a man in a hood instantly kills Cedric and ties up Harry. The man, Wormtail, drops the bundle he is carrying (Voldemort's current form) into a cauldron, as well as ashes from Voldemort's father, blood from Harry's arm, and Wormtail's own right hand. Voldemort resumes his body and rises from the cauldron. Voldemort presses a tattoo of the Dark Mark on Wormtail's arm, and suddenly Death Eaters begin appearing in a circle around them. Voldemort explains to Harry and his Death Eaters his fall from and rise back to power, and then he challenges Harry to a duel. Harry prepares for death, but he manages to use the disarming spell on Voldemort just as Voldemort cries "Avada Kedavra!" the killing curse, at Harry. The light from the two wands meets in midair and remains connected. Voldemort's past victims emerge from his wand and protect Harry once the wand connection is broken, giving him time to grab Cedric's body and touch the trophy, thus returning to Hogwarts.