Logan is part of the X-Men universe, but the story about an aged Wolverine and his dear friend, Professor Charles Xavier, is very different than anything that came before it.

[Warning: The following contains spoilers for Logan.]

When director James Mangold was in the early stages of pre-production on Logan, he wanted to include an opening prologue sequence that explained how Professor Xavier accidentally destroyed all of the X-Men. The reason he decided not to include it had nothing to do with the previous X-Men films and the ones that would certainly come after Logan. Mangold was concerned it would distract audiences from the real story on screen.

“I literally had written an opening which started with that sequence,” Mangold told IGN. “And so it was quite literal, who was dead. But the reason we didn’t do it wasn’t to spare other films, it was that it redefined the movie. It made the movie about the X-Men, instead of being about Logan and Charles. And irrevocably, when you read the script opening that way, it became about this other tragedy, as opposed to that tragedy being something hovering like a shadow in the background for these characters.”

The scene in question should be familiar to readers of the comic. Old Man Logan, which takes place in an alternate version of the X-Men universe, begins with the explanation that the universe’s supervillains had come together to defeat all superheroes. In the comic, it is eventually revealed that Wolverine was the one who destroyed his fellow X-Men, when Mysterio, a popular Spider-Man villain, created an illusion that made him believe he was killing enemies who threatened the students at the Xavier institute. Mangold decided to use this element in Logan, but have the X-Men’s deaths come at the hands of Professor X.

Instead of making an X-Men movie, Mangold managed to take two of the franchise’s most beloved characters and tell a genuinely sad and important story about friendship, loyalty and doing the right thing, even when everything seems, to be quite blunt, pointless. Logan has become one of the most well-reviewed and applauded X-Men movies since the series began in 2000, but Mangold hasn’t said if he’d be interested in returning to the franchise for another installment. Hugh Jackman, who has played Wolverine for 17 years, has said he’s officially done with the character.

Logan is currently available to buy from digital and physical retailers.