The central character in the series is Harry Potter, an English
boy who lives with his aunt, uncle and cousin, and who discovers,
at the age of eleven, that he is a wizard, though he lives in the
ordinary world of non-magical people known as Muggles. The
wizarding world exists parallel to the Muggle world, albeit hidden
and in secrecy. His magical ability is inborn and children with such
abilities are invited to attend exclusive magic schools that teach
the necessary skills to succeed in the wizarding world. Harry
becomes a student at Hogwarts School of Witchcraft and
Wizardry, a wizarding academy in Scotland and it is here where
most of the events in the series take place. As Harry develops through his adolescence, he learns to overcome the problems that face him: magical, social and emotional, including ordinary teenage challenges such as friendships, infatuation, romantic relationships, schoolwork and exams, anxiety, depression, stress, and the greater test of preparing himself for the confrontation, that lies ahead, in wizarding Britain's increasingly-violent second wizarding war.
Each novel chronicles one year in Harry's life during the period from 1991 to 1998. The books also contain many flashbacks, which are frequently experienced by Harry viewing the memories of other characters in a device called a Pensieve.
The environment Rowling created is intimately connected to reality. The British magical community of the Harry Potter books is inspired by 1990s British culture, European folklore, classical mythology and alchemy, incorporating objects and wildlife such as magic wands, magic plants, potions, spells, flying broomsticks, centaurs and other magical creatures, the Deathly Hallows, and the Philosopher's Stone, beside others invented by Rowling. While the fantasy land of Narnia is an alternate universe and the Lord of the Rings' Middle-earth a mythic past, the wizarding world of Harry Potter exists in parallel within the real world and contains magical versions of the ordinary elements of everyday life, with the action mostly set in Scotland (Hogwarts), the West Country, Devon, London and Surrey in southeast England. The world only accessible to wizards and magical beings comprises a fragmented collection of overlooked hidden streets, ancient pubs, lonely country manors and secluded castles invisible to the Muggle population.
When the first novel of the series, Harry Potter and the Philosopher's Stone (published in America and other countries as Harry Potter and the Sorcerer's Stone) opens, it is apparent that some significant event has taken place in the wizarding world – an event so very remarkable, even the muggles (non-magical people) notice signs of it. The full background to this event and Harry Potter's past is revealed gradually through the series. After the introductory chapter, the book leaps forward to a time shortly before Harry Potter's eleventh birthday, and it is at this point that his magical background begins to be revealed.
Harry's first contact with the wizarding world is through a half-giant, Rubeus Hagrid, Keeper of Keys and Grounds at Hogwarts. Hagrid reveals some of Harry's history. Harry learns that, as a baby, he witnessed his parents' murder by the power-obsessed dark wizard Lord Voldemort, who subsequently attempted to kill him as well. For reasons not revealed until the fifth book, the spell with which Voldemort tried to kill Harry rebounded. Harry survived with only a lightning-shaped scar on his forehead as a memento of the attack and Voldemort disappeared soon afterwards. As its inadvertent saviour from Voldemort's reign of terror, Harry has become a living legend in the wizarding world. However, at the orders of the venerable and well-known wizard Albus Dumbledore, the orphaned Harry had been placed in the home of his unpleasant Muggle relatives, the Dursleys, who kept him safe but treated him poorly, having him live in a cupboard and do chores while doting on their spoiled son, Dudley. Petunia Dursley was jealous of her sister's magical abilities as a child, and later came to believe that all wizards were freaks. Therefore, the Dursleys hated wizards, so they hid Harry's true heritage from him, saying his parents died in a car crash in the hope that he would grow up "normal".
With Hagrid's help, Harry prepares for and undertakes his first year of study at Hogwarts. As Harry begins to explore the magical world, the reader is introduced to many of the primary locations used throughout the series. Harry meets most of the main characters and gains his two closest friends: Ron Weasley, a fun-loving member of an ancient, large, happy, but poor wizarding family, and Hermione Granger, a gifted and very hardworking witch of non-magical parentage. Harry also encounters the school's potions master, Severus Snape, who displays a conspicuously deep and abiding dislike for him, and the Defence Against the Dark Arts teacher, Quirinus Quirrell, who later turns out to be allied with Lord Voldemort. The first book concludes with Harry's second confrontation with Lord Voldemort, who, in his quest for immortality, yearns to gain the power of the Philosopher's Stone, a substance that bestows everlasting life.
The series continues with Harry Potter and the Chamber of Secrets, describing Harry's second year at Hogwarts. He and his friends investigate a 50-year-old mystery that appears uncannily related to recent sinister events at the school. Ron's younger sister, Ginny Weasley, enrols in her first year at Hogwarts, and finds an old notebook which turns out to be a previous student's diary, Tom Marvolo Riddle, who later turns out to be Voldemort. The memory of Tom Riddle is inside of the diary and when Ginny begins to confide in the diary Voldemort begins to possess her. Ginny becomes possessed by Voldemort through the diary and unconsciously opens the "Chamber of Secrets", unleashing an ancient monster, later revealed to be a basilisk, which begins attacking students at Hogwarts. The novel delves into the history of Hogwarts and a legend revolving around the Chamber that soon frightens everyone in the school. The book also introduces a new Defence Against the Dark Arts teacher, Gilderoy Lockhart, a highly cheerful, self-conceited wizard who goes around as if he is the most wonderful person who ever existed, who knows absolutely every single thing there is to know about everything, who later turns out to be a fraud. Harry discovers that prejudice exists in the wizarding world, and learns that Voldemort's reign of terror was often directed at wizards who were descended from muggles. Harry also learns that his ability to speak the snake language Parseltongue is rare and often associated with the Dark Arts. The novel ends after Harry saves Ginny's life by destroying the basilisk and the enchanted diary which has been the source of the problems.
The third novel, Harry Potter and the Prisoner of Azkaban, follows Harry in his third year of magical education. It is the only book in the series which does not feature Lord Voldemort in any form. Instead, Harry must deal with the knowledge that he has been targeted by Sirius Black, his father's best friend, and, according to the Wizarding World, an escaped mass murderer who assisted in the deaths of Harry's parents. As Harry struggles with his reaction to the dementors – dark creatures with the power to devour on a human soul, which feed on despair – which are ostensibly protecting the school, he reaches out to Remus Lupin, a Defence Against the Dark Arts teacher who is eventually revealed to be a werewolf. Lupin teaches Harry defensive measures which are well above the level of magic generally executed by people his age. Harry came to know that both Lupin and Black were best friends of his father and that Black was framed by their fourth friend, Peter Pettigrew. In this book, a recurring theme throughout the series is emphasised – in every book there is a new Defence Against the Dark Arts teacher, none of whom lasts more than one school year.
During Harry's fourth year of school (detailed in Harry Potter and the Goblet of Fire), Harry is unwillingly entered as a participant in the Triwizard Tournament, a dangerous yet exciting contest where three "champions", one from each participating school, must compete with each other in three tasks in order to win the triwizard cup. This year, Harry must compete against a witch and a wizard "champion" from visiting schools Beauxbatons and Durmstrang, as well as another Hogwarts student, causing Harry's friends to distance themselves from him. Harry is guided through the tournament by their new Defence Against the Dark Arts professor, Alastor "Mad-Eye" Moody, who turns out to be an impostor – one of Voldemort's supporters named Barty Crouch, Jr. in disguise. The point at which the mystery is unravelled marks the series' shift from foreboding and uncertainty into open conflict. Voldemort's plan to have Crouch use the tournament to bring Harry to Voldemort succeeds. Although Harry manages to escape, Cedric Diggory, the other Hogwarts champion in the tournament, is killed by Peter Pettigrew and Voldemort re-enters the wizarding world with a physical body.
In the fifth book, Harry Potter and the Order of the Phoenix, Harry must confront the newly resurfaced Voldemort. In response to Voldemort's reappearance, Dumbledore re-activates the Order of the Phoenix, a secret society which works from Sirius Black's dark family home to defeat Voldemort's minions and protect Voldemort's targets, especially Harry. Despite Harry's description of Voldemort's recent activities, the Ministry of Magic and many others in the magical world refuse to believe that Voldemort has returned. In an attempt to counter and eventually discredit Dumbledore, who along with Harry is the most prominent voice in the wizarding world attempting to warn of Voldemort's return, the Ministry appoints Dolores Umbridge as the High Inquisitor of Hogwarts and the new Defence Against the Dark Arts teacher. She transforms the school into a dictatorial regime and refuses to allow the students to learn ways to defend themselves against dark magic.
With Ron and Hermione's suggestion, Harry forms "Dumbledore's Army", a secret study group aimed to teach his classmates the higher-level skills of Defence Against the Dark Arts that he has learned from his previous encounters with Dark wizards. An important prophecy concerning Harry and Lord Voldemort is revealed, and Harry discovers that he and Voldemort have a painful connection, allowing Harry to view some of Voldemort's actions telepathically. In the novel's climax, Harry and his friends face off against Voldemort's Death Eaters at the Ministry of Magic. Although the timely arrival of members of the Order of the Phoenix saves the children's lives, Sirius Black is killed in the conflict.
In the sixth book, Harry Potter and the Half-Blood Prince, Voldemort begins waging open warfare. Harry and his friends are relatively protected from that danger at Hogwarts. They are subject to all the difficulties of adolescence – Harry eventually begins dating Ginny, Ron establishes a strong infatuation with fellow Hogwarts student Lavender Brown, and Hermione starts to develop romantic feelings towards Ron. Near the beginning of the novel, lacking his own book, Harry is given an old potions textbook filled with many annotations and recommendations signed by a mysterious writer; "the Half-Blood Prince." This book is a source of scholastic success and great recognition from their new potions master, Horace Slughorn, but because of the potency of the spells that are written in it, becomes a source of concern. Harry takes private lessons with Dumbledore, who shows him various memories concerning the early life of Voldemort in a device called a Pensieve. These reveal that in order to preserve his life, Voldemort has split his soul into pieces, creating a series of horcruxes – evil enchanted items hidden in various locations, one of which was the diary destroyed in the second book. Harry's snobbish adversary, Draco Malfoy, attempts to attack Dumbledore, and the book culminates in the killing of Dumbledore by Professor Snape, the titular Half-Blood Prince.
Harry Potter and the Deathly Hallows, the last original novel in the series, begins directly after the events of the sixth book. Lord Voldemort has completed his ascension to power and gained control of the Ministry of Magic. Harry, Ron and Hermione drop out of school so that they can find and destroy Voldemort's remaining horcruxes. To ensure their own safety as well as that of their family and friends, they are forced to isolate themselves. As they search for the horcruxes, the trio learns details about Dumbledore's past, as well as Snape's true motives – he had worked on Dumbledore's behalf since the murder of Harry's mother. Snape is killed by Voldemort out of paranoia.
The book culminates in the Battle of Hogwarts. Harry, Ron and Hermione, in conjunction with members of the Order of the Phoenix and many of the teachers and students, defend Hogwarts from Voldemort, his Death Eaters, and various dangerous magical creatures. Several major characters are killed in the first wave of the battle, including Remus Lupin and Fred Weasley. After learning that he himself is a horcrux, Harry surrenders himself to Voldemort in the Forbidden Forest, who casts a killing curse (Avada Kedavra) at him. The defenders of Hogwarts do not surrender after learning of Harry's presumed death and continue to fight on. Harry awakens and faces Voldemort, whose horcruxes have all been destroyed. In the final battle, Voldemort's killing curse rebounds off Harry's defensive spell (Expelliarmus) killing Voldemort. Harry Potter marries and has children with Ginny Weasley and Hermione Granger marries and has children with Ronald Weasley.
An epilogue describes the lives of the surviving characters and the effects of Voldemort's death on the wizarding world. It also introduces the children of all the characters.