After being accepted to Hogwarts, Alex Deuyour and his mother, Desiree, go to Diagon Alley. While there, Alex learns that Harry Potter is at Gringotts and going to Hogwarts. Alex gets his school supplies and gets extra supplies. Alex receives permission to bring his pit bull Bandit to Hogwarts. Alex and Desiree meet the Weasleys and Longbottoms and the group have lunch together.
On September 1, Alex says goodbye to his mother and heads on the train. He sits with Ron Weasley and Harry, who he tells is his godbrother and second cousin. Alex also befriends another student, Kate Nguyen. Alex tells Harry about the wizarding world and tells him he was raised on both aspects and that he attended St. Gregory's Primary School with him and he tells him he didn't want to freak him out by telling him about the wizarding world. He tells Harry he's famous and defends Ron and Harry to his first cousin Draco Malfoy. At Hogwarts, Harry, Ron, intelligent Muggle-born Hermione Granger, Alex, and Kate are sorted into Gryffindor. The group become friends and quickly form the group "The Golden Couplet".
Alex finds that he enjoys school and particularly likes Transfiguration and Potions. During a flying class, Harry and Alex get places on the Gryffindor Quidditch team after Professor McGonagall sees them demonstrating their skills by stopping Malfoy from stealing Neville's Remembrall. On Halloween, Ron makes fun of Hermione, and Alex chastises him for it. Alex, Harry, Ron, and Kate save Hermione from the mountain troll and the group officially become friends. Alex and Harry prepare for their first Quidditch match, which ends with Gryffindor's victory. Harry, Ron, Hermione, and Kate suspect Professor Severus Snape jinxed Harry's broom, but Alex remains skeptical, partly because Snape is family and because Snape joined Dumbledore at the end of the first war. When Hagrid mentions Nicholas Flamel, Alex remembers that Nicholas Flamel was on Dumbledore's Chocolate Frog card.
After Christmas, Alex and the group discover Hagrid is housing a dragon. Believing Hagrid will get in trouble due to wizarding laws concerning dragons, Alex, Kate, Harry, and Hermione help get the dragon to Ron's older brother, Charlie, but are caught out of bed. All four are given detention with Malfoy and Neville. Harry and Alex discover Voldemort, but the centaur Firenze saves them. After Professor McGonagall dismisses them, Harry, Alex, Kate, Ron, and Hermione decide to stop whoever is after the Stones (who Harry, Kate, Ron, and Hermione believe to be Snape, while Alex correctly believes it to Quirrell). Harry helps Hermione get past the Devil's Snare and Harry gets a flying key. Ron "sacrifices" himself, and Hermione drinks a potion to help Harry and Alex get to the final obstacle. They encounter Quirrell (who has Voldemort on the back of his head) and during a struggle, Harry accidentally kills Quirrell. Harry and Alex wake up in the hospital wing and Professor Dumbledore tells them that the Philosopher's Stone has been destroyed. Harry, Ron, Hermione, Alex, Kate, and Neville's bravery helps Gryffindor win the House Cup. After the summer ends, Alex promises to stay in touch with his friends and the group hang out until they go separate ways.