Jog your memory: With the series' many plot twists, large and small, readers may have forgotten the stories that have come before. Below, a brief synopsis of the last four plots. NEW HARRY READERS BEWARE: KEY PLOT TWISTS ARE REVEALED!!!

Harry Potter and the Sorcerer's Stone

A young orphan boy, mistreated by his adopted family the Dursleys, discovers he is not just an unfortunate boy, but a wizard capable of magical feats. Sent to Hogwarts School of Witchcraft and Wizardry, Harry learns his new craft, while coming face-to-face with the evil Lord Voldemort, the Dark Force responsible for killing Harry's parents years ago.

• Ending: In a nail-biting scene, Harry confronts Voldemort. The evil power is so weak he is living through the body of Hogwarts Professor Quirrell. They battle - and when it's all over, Quirrell is dead, Voldemort is hanging on by a thread in some ethereal state, and Harry is alive and well enough to see another book.

Harry Potter and the Chamber of Secrets

On summer vacation from Hogwarts, Harry is warned by the house elf Dobby that danger awaits him if he returns to Hogwarts. He returns anyway, only to learn that the Chamber of Secrets has been opened and someone or something is petrifying members of the Hogwarts community.

Harry also finds a secret diary, made by a long-ago Hogwarts student who calls himself Tom Riddle. Harry begins corresponding with Riddle through the diary - only to learn that Riddle is actually Lord Voldemort.

• Ending: Harry enters the Chamber of Secrets to find Riddle and a 50-foot snake called a Basilisk. Riddle has been controlling the snake, which, in turn, has been responsible for all the petrifications at Hogwarts. Harry kills the snake and uses its fang to stab Riddle's diary - which causes Riddle to scream and disappear. Meanwhile, Harry and his friends are carted to safety by a Phoenix bird. It's uncertain whether Riddle - aka Voldemort - has survived.

Harry Potter and the Prisoner of Azkaban

Wizard murderer Sirius Black has escaped from the prison fortress of Azkaban, and Harry believes Black is after him. This causes great concern, as Harry and his Hogwarts teachers believe Sirius is the one who betrayed Harry's parents, resulting in their deaths.

• Ending: Harry learns that it was Peter Pettigrew, not Sirius Black, who betrayed his parents. Pettigrew has been living in the form of Harry's friend Ron's pet rat and is in consort with Lord Voldemort. After a climactic scene, Pettigrew escapes, and Harry and friends go back in time to save Sirius Black, who turns out to be Harry's godfather.

Harry Potter and the Goblet of Fire

Harry is chosen to participate in the prestigious Triwizard Tournament. To win, he must complete three difficult tasks. Meanwhile, the throbbing lightning-shaped scar on his forehead warns him that Lord Voldemort is near.

• Ending: Harry and his friend Cedric complete the three tasks of the tournament and touch the winner's trophy at the same time. This creates a "portkey" that transports them to another dimension, where Lord Voldemort is waiting. Voldemort's consort, Peter Pettigrew, kills Cedric. But Harry escapes - with help from his mother who appears in ghost form - and returns to Hogwarts, where he learns that a Professor Moody impostor was responsible for placing him in danger. Worse, Harry and the staff at Hogwarts now recognize that Voldemort is strong and lurking in the wings.