Harry Potter and the Cursed Child
by J. K. Rowling
The play is divided in two parts, consisting of two acts each.
In the opening scene, set during the epilogue of Deathly Hallows in the year 2017, Harry and Ginny Potter send their son, Albus Severus, on the Hogwarts Express to begin his first year at Hogwarts. Harry works a desk job as the Head of Magical Law Enforcement at the Ministry of Magic, while Ginny is the editor of the sports section of The Daily Prophet. Ron Weasley and Hermione Granger also send their daughter Rose on the train. Hermione is now Minister of Magic, while Ron manages Weasley's Wizard Wheezes in Diagon Alley. On his first trip aboard the Hogwarts’ Express, Albus makes an unlikely friendship in Scorpius Malfoy, the son of Harry's former nemesis Draco and his wife Astoria (née Greengrass). The school is stunned when, in a break with the tradition of Potters being sorted into Gryffindor, Albus is sorted into Slytherin alongside Scorpius.
Both boys are bullied by other students over the next few years, Albus due to his perceived failure to live up to his parents, Scorpius due to unproven rumours that he is the son of Lord Voldemort. Scorpius's mother then passes away due to a fatal disease. In addition, Albus and Harry drift apart due to Albus's struggles with his father's shadow and Harry's uncertainty on how to deal with his son's problems. Albus also drifts apart from Rose, with whom he was close before meeting Scorpius. Prior to his fourth year, Albus gets into a fight with his father after being given the latter's baby blanket and a love potion from Ron. During the fight, Harry says that he sometimes wishes Albus was not his son, and Albus spills the potion on the blanket.
Harry obtains a prototype of a more powerful version of the Cedric. After overhearing Harry refuse to help the Diggorys, Albus is inspired to do so himself and convinces Scorpius to help him. The two escape from the Hogwarts Express and the trolley witch. The two arrive at St. Oswald's Home for Old Witches and Wizards in Yorkshire, where Amos lives, and team up with Delphi to steal the Time-Turner from Hermione's office, in the Ministry of Magic, while disguised with Polyjuice Potion.
Knowing that Cedric's death was the result of him winning the Triwizard Tournament alongside Harry, the boys use the Time-Turner to travel back to the first tournament challenge in 1994. The two disguise themselves as Durmstrang students in an attempt to sabotage Cedric to prevent his victory. The plan fails, and the disguises cause Hermione to become suspicious of Viktor Krum, a Durmstrang student, and go to the Yule Ball with Ron instead. As a result, Ron never experiences the jealousy fundamental to his relationship with Hermione, and the two never marry. Ron instead falls in love with Padma Patil at the Ball, and Hermione becomes a frustrated and mean professor at Hogwarts, teaching Defense Against the Dark Arts.
Meanwhile, Harry has nightmares about Voldemort as he grows suspicious that the wizard will return. A centaur named Bane tells Harry that a "dark cloud" is around Albus. Convinced that Scorpius is a threat to Albus, Harry tries to have the boys kept apart at Hogwarts by attempting to force Headmistress Minerva McGonagall to keep tabs on Albus using the Marauder's Map.
Albus and Scorpius's friendship is destroyed, but the two eventually reconcile after Albus steals Harry's old Invisibility Cloak from Albus's older brother James Sirius. Harry is persuaded to relent after a conversation with Draco and Ginny. Meanwhile, Albus and Scorpius make another attempt to use the Time-Turner to change Cedric's fate, this time by humiliating him during the Triwizard Tournament's second task. When Scorpius returns to the present day, however, Albus is not with him. Dolores Umbridge walks up to him and reveals that Harry is dead and Lord Voldemort rules the wizarding world. Scorpius follows Umbridge back to Hogwarts as Dementors fly around the auditorium and a banner with the Dark Mark is revealed.
Scorpius discovers that – as a result of his actions – an embittered Cedric joined the Death Eaters and killed Neville Longbottom during the events of Deathly Hallows, preventing him from killing Nagini and allowing Voldemort to win the Battle of Hogwarts. With Harry now dead, Albus subsequently never existed, while Voldemort was able to completely consolidate power and transform the Ministry of Magic into a dictatorial regime. In the new timeline, Scorpius became a popular Head Boy and Quidditch star, helping the staff and students torment Muggle-borns. Dolores Umbridge became the new Headmistress of Hogwarts and patrols the school with Dementors and a revived Inquisitorial Squad led by Scorpius. Draco Malfoy occupies Harry's old position as the Head of Magical Law Enforcement, using his post to encourage routine attacks on Muggles and bribe the Prime Minister to remain silent on the actions of the Death Eaters.
A powerful dark figure called "The Augurey" leads the Ministry of Magic. With help from Ron, Hermione, and Severus Snape, now the final members of a dwindling anti-Voldemort resistance movement, Scorpius is able to use the Time-Turner to prevent the interference of Albus and his past self and restore the events of the original timeline; the alternate Ron, Hermione, and Snape sacrificing themselves to the Dementors in order to allow him to do so. Scorpius reunites with Albus, and the two boys are eventually found by their parents, as well as Ron and Hermione. Following these events, Harry scolds Albus for his actions, but the two nevertheless begin to reconcile.
Realising the danger the Time-Turner poses and deciding their parents will continue to keep it (as Hermione had done in the Ministry of Magic), Scorpius and Albus attempt to destroy it themselves, but they are joined by Delphi Diggory. Scorpius realizes that Delphi was in charge of the Ministry of Magic in the alternate timeline (from her tattoo of the wings of a magical bird, which she says is called an Augurey), and she takes them captive, later revealing her intention of restoring the alternate timeline. A fellow student, Craig Bowker Jr., tries to intervene as Delphi holds Albus and Scorpius captive on the Quidditch pitch, and Delphi murders him.
After Ron reveals he saw Albus and Scorpius with Delphi while he was in Hogsmeade with Neville Longbottom, Harry and Draco confront Amos, only to discover Delphi is not his niece but had placed Amos under a confundus charm. Delphi takes the boys to the final challenge of the Triwizard Tournament, but Albus and Scorpius prevent her from acting, and Delphi uses the Time-Turner again to travel farther back in time. She inadvertently takes the boys with her and then destroys the Time-Turner to leave them all stranded in time.
Searching Delphi's room, Harry, Draco, Ginny, Hermione, and Ron discover hidden writing on the walls describing a prophecy that will allow Voldemort to return. Draco questions why she would be so obsessed with Voldemort's return, as Ginny finds writing on the ceiling that claims Delphi is the daughter of Voldemort.
In a real-world depiction corresponding to the change in history, the concession store in the foyer of the theatre also changes and sells shirts, mugs, hoodies, and other memorabilia with Voldemort logos, not available during Acts One and Two.
Abandoned by Delphi in the past, Albus and Scorpius discover they have been taken back to the night before Harry's parents were killed at Godric's Hollow (31 October 1981), and assume Delphi is planning to kill Harry before Voldemort attempts to do so (which severely weakens Voldemort). Albus and Scorpius write an invisible message on Harry's baby blanket, knowing in the present (which is now also the night of the anniversary of the death of Harry's parents, when he often looks for his blanket as it is the only physical memento he has), the blanket would become stained with a love potion and expose the message to Harry.
Meanwhile, Draco reveals the Time-Turner was actually a prototype for a perfected model owned by him (it was made for his father), but they remain unable to rescue the boys due to their uncertainty over which time period they have entered. After Harry receives the message from the boys, he and his allies use Draco's Time-Turner to travel back in time to save them and stop Delphi. While waiting for Delphi, they deduce she intends to convince Voldemort to abandon his doomed attempt to kill Harry, ensuring her father's survival and allowing her to be with him.
Harry disguises himself as Voldemort using Transfiguration to distract Delphi, during which Delphi reveals that Bellatrix Lestrange is her mother and after a struggle, the group manages to subdue her. Rather than killing Delphi, it is decided that she will be brought to Azkaban Prison. Lord Voldemort then appears and is oblivious to the presence of Harry and the group. The group allows the murder of Harry's parents to play out again, unwilling to risk the consequences of altering the past.
They all stand with Harry to watch the sad event replay. After returning to the present day, Delphi is sent to Azkaban. Albus and Scorpius now decide to be more active at Hogwarts, with Scorpius expressing interest in trying out for Quidditch and asking Rose on a date. Harry and Albus visit Cedric's grave, with Harry apologizing for his role in Cedric's death.