Leading up to the 15th anniversary of Harry Potter and the Sorcerer’s Stone on November 16, we’re looking back on the series and rewatching one movie each week to see how they hold up.

Revisiting the Harry Potter movies each week, I’ve realized how different they are from major franchises that fill movie theaters today. Unlike the Marvel and DC Cinematic Universes, James BondTransformers or The Fast and Furious franchises, the Potter films follow one main arc. Instead of spinoffs and origin stories, there’s a beginning, a middle, and an end across these eight movies, charting one hero’s singular journey. You can sit down and watch any Bond film or an Avengers movie and walk away pretty satisfied. But with Potter, each installment builds upon the last, and reflects the strength of the series as a whole.

The Half-Blood Prince made me appreciate the breadth of the franchise the most. It’s a film you can watch and enjoy on its own, but its true strength lies in how it fits within the larger context of the series. The sixth movie escalates the budding terror of the fifth film, explores the dark flip side of allegiances, and prepares the audience for what’s to come in the two-part finale. It’s the Potter movie in which the grim reality of the wizarding world begins to feel palpably real, and when Harry (Daniel Radcliffe) must learn to leave his adolescence behind.

I wrote a few weeks ago that The Goblet of Fire is when the Potter movies started growing up; in Order of the Phoenix we see the Hogwarts students begin to mature as they take the revolution into their own hands, but in Half-Blood Prince that fight leaves the hallways of Hogwarts and enters the rest of the world. This is the movie where things start to feel bigger than just a kid fighting creatures on magical adventures; in Half-Blood Prince the Potter movies become metaphors for oppression, tyranny, and survival.

Half-Blood Prince wastes no time establishing how grim the world has become — not even the opening titles are spared. The cheerful Potter music is no more, replaced with a slow, melancholic version of the theme song that plays as the camera glides past the most depressing WB logo you’ve ever seen. As soon as I sat down to rewatch the movie last week with a friend, I exhaled heavily in preparation for a not-so-fun Potter movie. It’s my favorite of the series, but watching it days after the 2016 election results was an even bigger bummer. (Don’t get me wrong, I’m not endorsing the recent memes and jokes that align Voldemort with Trump, mainly for how naive and insensitive they are.) But as much of a downer as this movie is, I appreciate the darkness in Half-Blood Prince for how well it transitions from films five to seven and eight.

Warner Bros.

While the fear of Voldemort lurks within the previous movies, director David Yates captures the omnipresence of that mood in Half-Blood Prince. One of the more striking images in this film is the exterior shot of the Hogwarts Express — every other movie finds the train racing through lush greenery or snow-covered land, but here the train cuts through the dry brown earth of the British countryside. Maybe Yates is simply showing us a new area we’ve yet to see on the train’s route, but within the context it feels like a hint at the decaying atmosphere all around.

Yates continues to evoke the presence of Voldemort (who isn’t even in this movie as an adult) with the help of Bruno Delbonnel’s (Inside Llewyn DavisAmelie) cinematography. The film, which is one of the best photographed of the series, has the most brooding visual palette of all eight movies. Nearly every frame is stripped of color, beginning with the thick London fog in the opening Death Eater attack on the Millennium Bridge (a reminder that even the Muggles are no longer safe). Delbonnel cloaks the film in grey, charcoaled hues to remind you of the gloomier days Harry now occupies. Yates also borrows from The Chamber of Secrets to visualize the menacing power of Tom Riddle, using a similar green-tinted aesthetic in the flashbacks of Tom as a boy. As much as I hated how Christopher Columbus implemented that approach in the second movie, here it works well since Yates uses it sparingly.

In many ways The Half-Blood Prince is the darker companion to The Order of the Phoenix. The fifth movie focused on the idea of unity through friendship and love (i.e. Dumbledore’s Army, Harry rejecting Voldemort’s control with his memories), but the sixth installment looks at the flip side of that: Unity through fear and coercion. Some of the film’s best scenes are ones that explore the machinations of Voldemort’s following, and the threats and terror that define his allegiances. Snape making the Unbreakable Vow with Narcissa Malfoy and Draco’s near-mental breakdown in the school bathroom are some of my favorites for how well they show the emotional toll Voldemort’s villainy has taken on his followers. Though we later learn Snape’s true intentions, Alan Rickman plays his secrecy well, yielding one of his finest performances in the series. (Let’s be honest, Rickman is the real MVP of this franchise). And as much as we’ve hated Draco for years, in this movie we begin to sympathize with him for the first time.

Warner Bros.

What I love most about The Half-Blood Prince is how it smoothly shifts between the macro and the micro emotions of J.K. Rowling’s novel. Aside from apocalyptic fears, it also portrays teenage heartbreak and jealousy in a realistic way. The Goblet of Fire showed the immature, temperamental impulses of teenage crushes, but in Half-Blood Prince Hermione finally acknowledges her feelings for Ron. Admittedly, the raging hormones in this movie are a bit silly and obnoxious (there’s way too much of fawning Lavender and horny McLaggen, and I still don’t buy Ginny and Harry’s romance). But the scenes between Hermione and Ron have a sincere warmth. Plus, Ron finally gets some of his funniest moments thanks to Professor Slughorn’s love potion.

What makes The Half-Blood Prince the best Harry Potter movie — and what makes Rowling’s book one of the best — is how it captures the most formative moment in Harry’s journey: Dumbledore’s death. Without his trusted headmaster and sage, and with his trust in Snape lost, Harry is forced to not just grow up, but become independent. He learned the prophecy in Order of the Phoenix and gained the strength of love and friendship, but Half-Blood Prince prepares him for his most daunting task yet. On its own, the sixth film is a good Potter movie, but it’s best remembered as the film that forms the emotional crux of the franchise.

Additional Thoughts:

  • I might have been in a heightened emotional state when watching this, but the Dumbledore cave scene still ruins me.
  • Helena Bonham Carter is Bellatrix Lestrange. If Warner Bros. decides to have any more spinoffs, I could get behind a Bellatrix origin story.
  • I completely forgot Freddie Stroma played the cocky McLaggen, which makes his casting in Season 1 of UnReal even better.
  • Coked out Harry Potter (aka Harry on Liquid Luck) is my favorite version of Harry Potter.
  • Some of the best visuals in this movie occur during the Pensieve sequences, which received a major upgrade since the shoddy CGI in Goblet.

Harry Potter Movie Ranking (So far):