Still mourning the loss of Sirius and shaken by a prophecy that predicted he would either kill or be killed by Lord Voldemort, Harry was in a very dark place by his sixth year.

But events took an even more intriguing turn, as Professor Dumbledore taught Harry all about Voldemort’s history, Hogwarts got a new Potions master and a cryptic figure called the Half-Blood Prince added even more mystery to proceedings.

Oh, and Harry realised he liked his best friend’s sister, too. Just another casual year at Hogwarts.

Professor Slughorn

Severus Snape finally nabbed the Defence Against the Dark Arts job, so this year Hogwarts got a new Potions Master. Or in this case, an old Potions master in the shape of the reluctant former Head of Slytherin house, Professor Horace Slughorn.

Slughorn loved to bask in the reflected glory of the famous witches and wizards he befriended as a teacher, so Harry proved too tempting a famous wizard to pass up when Dumbledore invited him to rejoin the staff.

It wasn’t long before his ‘Slug Club’ (an exclusive club that Slughorn only invited esteemed witches and wizards to) was back in full swing. It was the first of many things Slughorn brought with him to Hogwarts, revealing himself to be a truly fascinating bloke.

The Half-Blood Prince

Not exactly the greatest potions-maker of all time, Harry found himself suddenly very talented at the subject when he acquired an old Potions textbook previously owned by the ‘Half-Blood Prince’.

Harry’s grubby old book was crammed with shortcuts and homemade spells that help him cut corners in class. Not all was as it seems, and Harry discovered that Severus Snape was the man behind the helpful scribbles. You’d think after Tom Riddle’s diary and the vicious Monster Book of Monsters, Harry would know not to trust books by now.

Harry and Ginny

Harry had dealt with a number of great adversaries in his time, but in Half-Blood Prince it was a crush on Ginny Weasley that he had to try to vanquish. Like many teenage boys, it wasn’t until Ginny started going out with someone else that Harry realised that he actually liked Ron’s little sister.

His confused feelings triggered the traditional teenage angst, jealousy and lovelorn dreams. Never mind Death Eaters, teenage crushes are the worst.

Horcruxes

Before his return in Goblet of Fire, Voldemort existed to Harry in a sort of ‘half form’, but in Half-Blood Prince we found out why Voldemort was never entirely gone.

As Dumbledore explained, Voldemort was kept alive by Horcruxes; fragments of his soul that were created every time he performed a horribly evil deed. Harry must destroy these Horcruxes (which could be absolutely anything) and venture with Dumbledore into the Pensieve to learn all about the Dark Lord’s history. How far away the days of making feathers float seem now.

Felix Felicis

Probably one of the best potions ever, Slughorn introduced Harry and his class to Felix Felicis, otherwise known as ‘liquid luck’.

This potion blessed the drinker with good fortune for a limited time. Harry won some in a potion-making competition, and he embarked upon a very action-packed night, which ended in…

Aragog’s funeral

After being tasked with the near-impossible mission of trying to obtain a memory of Professor Slughorn’s that the professor had attempted to ‘edit’, Harry’s slurp of Felix led him to Hagrid’s Hut.

On the way Harry bumped into Slughorn, who learnt that Hagrid’s Acromantula friend Aragog was dead. Since Acromantula venom was worth a pretty penny, Slughorn tagged along to the funeral. A wine-soaked evening later, Harry had the memory and we enjoyed one of our favourite-ever scenes.

Lav-Lav and Won-Won

The Hermione and Ron will-they-won’t-they saga took a rather infuriating turn this year, with the pair going to incredible lengths not to be together. For this, we entirely blame Ron. Or should we say Won-Won.

Over sixth year, Ron became romantically entangled with Lavender Brown, despite only having a mutual interest in each other’s tonsils in common. The schmaltzy sweetheart necklace and their public displays of affection got just about everybody’s attention.

Draco, the reluctant Death Eater

Draco’s days of being the name-calling, stereotypical school bully seemed a thing of the past by year six, when he joined the Death Eaters. How far he’d come from making ‘Potter Stinks’ badges.

He was assigned a terrible task by Lord Voldemort, and the usually arrogant and swaggering Draco seemed more subdued. In a shocking reveal, Harry learnt that Draco had been tasked with the murder of Dumbledore. A more shocking twist, perhaps, was that Draco couldn’t do the deed. He might have been a bit of a git sometimes, but Draco proved he’s no killer.

Dumbledore’s bravery

Ill-judged relationships and the Half-Blood Prince aside, the main event that rocked this story was the death of Professor Dumbledore, who went out in an incredible final act of bravery.

The scene in the cave is a hard read; Dumbledore in terror was something we were not prepared for. With Harry’s help, he battled through and the pair escaped with the (fake) Horcrux... but Dumbledore was weakened by the cursed potion left by Voldemort.

Dumbledore returned to Hogwarts to find Draco and a pack of Death Eaters had him cornered. It was Professor Snape who killed the headmaster who taught Harry so much, devastating him and the rest of the school. But Dumbledore didn’t die in vain.

Harry knew what he had to do…

While both shocking and unbelievably tragic, the death of this kind, clever, guiding hand gave Harry the momentum he needed to hunt down Voldemort’s Horcruxes.

It was the death scene heard around the world as millions of readers screamed ‘NOOO!’ at their copies of Half-Blood Prince. Snape finally became the villain Harry thought he was, and readers had to wait two years to find out what happened next.