Fast & Furious is no stranger to high-profile divorces. Face of the franchise Vin Diesel famously passed on 2003’s 2 Fast 2 Furious, believing a follow-up would harm the original’s chances at being remembered as a classic—only to return at the end of 2006’s The Fast and the Furious: Tokyo Drift and subsequently make six more sequels and counting. Dwayne Johnson later provided a spark with his arrival in 2011’s Fast Five, helping Fast reach new heights and eventually landing his own spin-off, 2019’s Hobbs & Shaw. But Johnson sat out last year’s F9, and amid his very public beef with Diesel, he later declared that he won’t take part in the two upcoming films that are set to conclude the saga.

Yet Tuesday’s shocking announcement that Fast stalwart Justin Lin, whom Diesel has called a “forefather” and “architect” of the series, will no longer serve as director of the already in-production Fast X might be the most troubling speed bump to date.

No filmmaker other than Lin has directed more than one Fast film. Even more importantly, he’s responsible for essentially reviving the now $6-billion franchise, which appeared to be slowing down when Lin first came aboard for the Paul Walker-less third film, Tokyo Drift. Originally viewed as a smaller direct-to-DVD vehicle, Lin instead made a fan favorite that was enough of a commercial success to pave the way for the O.G. cast’s reunion in 2009’s Fast & Furious, also directed by Lin. The franchise’s record-breaking fourth installment cemented Fast as a property to be reckoned with.

Lin would continue to deliver bigger films and bigger box-office returns with Fast Five, the consensus franchise peak, and Fast & Furious 6. After sitting out Furious 7 and The Fate of the Furious, he rejoined the family for F9, a $700-million hit released in the middle of a pandemic. Back in the fold, the trusted veteran was set to helm Fast X and Fast 11, which have been billed as a two-part send-off. Only days ago, Diesel posted an Instagram video with Lin to celebrate the first week of Fast X production.

“It feels like the beginning of an epic ending,” said Lin—though in retrospect, he appears to be truly ready for an ending. He’s stoic in the clip, giving a steady dose of nods and short answers, and capping it off with a solid shoulder shrug. “Is it fair to say that this will be the best one?” Diesel asks. “In my heart, yes,” Lin replies, earning a gleeful reaction from his powerful star-producer.

Well, this was one fast change of heart. On Tuesday, Lin was suddenly out, though Deadline called his exit “amicable”—despite “creative differences.” In a statement of his own, Lin said, “With the support of Universal, I have made the difficult decision to step back as director of Fast X, while remaining with the project as a producer.”

Fans are rightfully nervous about what the loss of Lin will mean. He’s proven to be one of the premier action filmmakers working, as demonstrated by any number of his insane Fast set pieces—from the Fast Five favela chase, to the world’s longest runway in Fast & Furious 6, to actually going to goddamn space in F9. Oh, and let’s not forget that this man dragged a safe through Rio de Janeiro! It’s hard to name a director that’s been responsible for more “Holy shit, I can’t believe they just pulled that off” grins than Lin. Even Diesel knows how crucial Lin has been to the franchise’s success. “You wanted 9 and 10 to be incredible,” he said in a social media video upon revealing the presence of Lin and his likely return ahead of F9. “We’ve heard your concerns about the saga and where it needs to arrive in its final chapters.”

Lin’s most important attribute is probably his love for Fast and its characters, particularly one that he created years before Fast was on his radar. Lin and actor Sung Kang first brought Han, a small-time criminal with a large appetite, to life in 2002’s Better Luck Tomorrow, their well-received low-budget drama about a group of Asian American high school students who develop a taste for the wrong side of the law. When Lin landed the Tokyo Drift gig, he made the unexpected call to insert Han into the story as a mentor to reckless new main character Sean Boswell (Lucas Black). Han appeared to die late in the film, and though Diesel made a cameo in its final scene, Lin had no grand plan to continue with the series, either. “After Tokyo Drift, I told the studio, ‘I’m done, I think I’m going to go back to the indie world,’” he told me last year.

Then he changed his mind. While driving to San Francisco with his future wife and Kang, their group was swarmed by Han fans, at an Arby’s, of all places. “It was the first time feeling that kind of impact,” Lin said. “I still remember, I was driving on the on-ramp back after lunch and I said, ‘God, it’s too bad Han is dead.’ Sung looked at me and said, ‘Does he have to be?’”