Here is a brief summary of each of the Harry Potter books. You may need to add more details to these summaries depending on how long they need to be. You can find more details in the eNotes summaries of these books. Links to two of these summaries are included below.
Harry Potter and the Sorcerer’s Stone: Harry is left with his relatives, the Dursleys, who treat him badly. He learns that he is a wizard and starts school at Hogwarts. With help from his friends, he prevents Voldemort from obtaining the sorcerer’s stone, which would have enabled Voldemort to get a body again.
Harry Potter and the Chamber of Secrets: During the year, a series of students (and a cat and a ghost) are petrified. The culprit is young Voldemort’s soul, which has possessed Ginny Weasley, who releases a basilisk that attacks the students. Harry saves Ginny, kills the basilisk, and destroys the diary that held Voldemort’s soul.
Harry Potter and the Prisoner of Azkaban: Sirius Black has escaped from Azkaban and apparently wants to kill Harry. Everyone believes he was a Death Eater who betrayed Harry’s parents. Harry finds that Sirius is innocent and prevents him (and a hippogriff) from being unjustly executed.
Harry Potter and the Goblet of Fire: The Tri-Wizard Tournament is held (for the first time in 202 years) at Hogwarts. It turns out to be an elaborate plot to bring Harry to Voldemort. Voldemort uses Harry’s blood to help make himself a new body, but he fails to kill Harry.
Harry Potter and the Order of the Phoenix: The Ministry of Magic tries to take over Hogwarts, sending the evil Dolores Umbridge to, in essence, run the school. Harry resists her and the ministry. All year, he is plagued with visions that eventually lead him and his friends to battle Voldemort and the Death Eaters at the Ministry of Magic.
Harry Potter and the Half-Blood Prince: Harry spends most of this book learning about Voldemort’s youth. Dumbledore shows him many memories of Voldemort’s youth so that Harry will be able to fight Voldemort. Harry learns that Voldemort has divided his soul and cannot be killed until all the pieces of the soul are found and destroyed.
Harry Potter and the Deathly Hallows: Voldemort controls the Ministry of Magic so Harry, Hermione (and sometimes Ron) are fugitives. They hide from Voldemort’s people and seek the horcruxes that house the pieces of Voldemort’s soul. A final battle between Voldemort’s forces and the forces of good occurs at Hogwarts.