I have a confession to make. I know the secret behind one of the biggest mysteries in Detective Pikachu.

I have known the truth for over a year now, and I cannot stay silent any longer, primarily because Warner Bros. has officially lifted the embargo on what I learned when I visited the set of Detective Pikachu just outside of London so many moons ago. The answer may surprise you, it may shock you, and it is almost definitely something that could be considered a spoiler, so if you want to go into this movie as though you were on the receiving end of a Sand Attack—which is to say, blind—then you should probably stop reading right here.

The Mystery of DETECTIVE PIKACHU’s Purple Eyes Explained_1

Okay, now that all the spoilerphobes have blasted off again, let’s get down to brass tacks. One of the biggest questions raised by the latest Detective Pikachu trailer was, “Why is Mewtwo so damn smooth?” But I don’t have a good answer for that one. What I do have an answer for is why characters like Mewtwo, Charizard, and Aipom all had glowing purple eyes and were seemingly hyperaggressive.

While this may not come as much of a surprise to those who played the Detective Pikachu game on the Nintendo 3DS, it’s a vast conspiracy that likely involves Tim Goodman’s missing father Harry, that suspicious-looking lab, Mewtwo, underground Pokémon fight clubs, and performance-enhancing drugs. It’s the kind of juicy scandal that seems primed for a tell-all Netflix documentary five to ten years down the line, except it’s unclear if streaming services are a thing in the world of Pokémon. Since they can literally upload these pocket monsters to the cloud, something tells me “yes,” but that’s a question for a different article.

While visiting the set with a group of assembled press, I found myself standing in what looked like the set of Nickelodeon’s Roundhouse crossed with a cybergoth rave. That comparison is fitting because it’s an underground Pokémon fighting arena / maybe a nightclub as well called “Roundhouse,” and it’s where Pikachu has his woefully mismatched battle with a seriously angry Charizard. It’s a club owned by Sebastian, a pop star with a Charizard tattoo on his chest, played by Mexican actor Omar Chaparro. Sebastian is willing to go to extreme lengths to win the battle, and in the scene we watched, he injects his prize Charizard with some sort of drug that increases its aggressiveness.

The match is clearly important and since Sebastian has access to these mystery drugs, there’s obviously a good reason why Detective Pikachu is risking his life and limbs against a giant fire lizard ten times his size.

“It’s actually a rematch, because a month ago Pikachu and my Charizard had a fight, a battle, and he almost wrecked my Charizard,” Chaparro explained. “He also wrecked my coat, as you can see, with his thunderbolt. So I’m very excited to have a rematch. Actually I told Tim that if he gives me a rematch, I could tell him everything he needs to know.”

Director Rob Letterman, perhaps sensing that we were onto the truth, danced around the question and instead explained why creating a big Pokémon battle set piece is one of the most challenging sequences in the entire film.

“So, Pokémon are battling in the arena, but people in the audience also have their Pokémon with them, [so] we have to leave space for that,” Letterman said. “We have to create eyelines for all of that. We have to interact with that. In this case, Charizard—you probably know if you really geek—Charizard’s tail is on fire all the time so we have to put a mic that represents the fire tail and whenever he blows flame we have to have another light that lights the crowd. It’s insane. And, on top of that, I added insult to injury for the entire crew. I wanted to shoot on film. So I made it extra, extra complicated. But it looks amazing.”

Great—glad you could make life more difficult for everyone involved, Rob, but that still doesn’t answer our question. Thankfully, actor Justice Smith, who stars as Detective Pikachu’s unwitting partner Tim Goodman, gave us a much-needed clue. In between takes, Smith and his co-star Kathryn Newton, who plays a wannabe investigative reporter named Lucy, joined us for a Q&A all about the film.

Justice Smith: “So, Tim and Pikachu meet Lucy, who gives them a tip that there’s this gas … Kathryn? Are you listening, just to make sure that I don’t give away things that I’m not supposed to? So, Lucy gives Detective Pikachu and Tim this tip that there’s this gas that’s making Pokémon go crazy. Can I say that?”

Interviewer: “She’s like, well, you did.”

Smith: “Should I not say that, and what should I…? Anyway, so they go to find out where this is coming from, and it leads them to this arena, this underground arena, where people are battling Pokemon illegally. Because in Ryme City, Pokémon and human exist harmoniously. So they’re … they’re drugging these …”

Kathryn Newton: “We can see he’s doing that, so…”

Smith: “Yeah, so they’re drugging these Pokémon and making them fight against their will. Which is, you know, really messed up.”

A-ha! So what is this mysterious drug that’s driving Pokémon berserk? Those who have played Detective Pikachu are probably shaking their heads with a knowing smile right now because it sounds almost identical to a major plot point from that game: chemical R. Created at a high-tech laboratory, this chemical was designed to be some sort of magical cure-all miracle drug that was derived from Mew’s DNA. However, they accidentally used Mewtwo’s DNA instead, which contained a gene that caused all those who ingested it to fly into hyper-aggressive rages.

Naturally it follows that this is going to be one of the major mysteries of Detective Pikachu, too. We have one answer now, but so many more questions. Who is producing this drug? What kind of experiments are they performing on Mewtwo at that lab we saw in the trailer? Is this what Harry Goodman was investigating before he went missing? Is he still alive? Is Mewtwo under chemical R’s influence too or are its eyes just naturally violent and violet? We’ll have to wait a little over a month to find out.

Detective Pikachu hits theaters on May 10. Stay tuned for even more inside scoops from our time on the film’s set!

Images: Warner Bros/Legendary

Editor’s note: Nerdist is a subsidiary of Legendary Digital Networks.