The Season 3 finale of the NBC series Grimm had so many memorable and jaw-dropping moments, and fans will have to wait until the fall season to get answers. In the meantime, we got on the phone with actor Silas Weir Mitchell (who plays Monroe, a reformed Blutbad and best friend to Grimm/Detective Nick Burkhardt) to talk about all of the craziness this season and look ahead to Season 4.

During the interview, he talked about his reaction when he first read the finale, getting an extra couple of days to shoot because of everything in it, what he found most surprising about the episode, how awesome their final wedding outfits were, his concern that Monroe and Rosalee (Bree Turner) might never actually get to say their vows, the great complication that Monroe’s parents provided this season, finally learning how Wesen know when someone is a Grimm, adding another Grimm to the mix, and how what’s happened to Nick (David Giuntoli) might affect their friendship. Check out what he had to say after the jump, and be aware that there are some spoilers.

Collider: What an awesome season finale!

SILAS WEIR MITCHELL: I’m so glad. That’s great to hear. It was fun making it. It felt like we were doing something right, but that doesn’t always translate.

When you read the script for the finale, what was your reaction to it?

MITCHELL: It felt to me like, “How the hell are they going to do this in eight days?!” And they didn’t do it in eight days. We actually got 10 days on this one. Because it was so big, it just felt like it was a monster. So, my first thought was very practical. I wondered how they were going to cram all of that action into one episode. There were 89 scenes, and usually there’s about 60 scenes. There were a third as many scenes as usual. And then, the next thing I thought after that was, “Thank god, Norberto [Barba] is directing it.” We knew that we’d be in very good hands with that guy. He really, really knows what he’s doing. He’s very, very astute, as far as the storytelling goes. And because he’s a producing director, he can do things and it doesn’t take as much time as other people because he doesn’t have to run it up the flagpole. He can just say, “I approve this,” and then shoot it that way. Whereas other directors, that are guest directors, which is 90% of the directors – Bert directs maybe four episodes a year – have to ask, “Do you think we can do it like this?” Bert doesn’t have to ask those questions. You’re in very good hands when he’s behind the wheel.

Were there any moments in the finale that you found particularly surprising?

MITCHELL: The mayhem of when Trubel comes in with the vial for Nick at the wedding. That was just incredible. We shot that scene over two days. It was just one of those things where, every day you show up to work and there’s some variation of, “How the hell are we ever going to get through this day?” There’s always some sense of that emotion running through because you always feel like you’re at the foot of a giant mountain. This felt like Mt. Everest. It was one of those days where that feeling was truly genuine. I didn’t know how we were going to get all of that, in the time that we had.

That was also probably the best dressed fight scene that I’ve ever seen.

MITCHELL: Yeah! That was a pretty cool suit. That’s a real suit from Austria. It’s the southern German traditional garb.

It was such a great moment, when Monroe told Rosalee’s sister that they didn’t really care that she ruined the wedding dress because they both hated it.

MITCHELL: That was funny! That was fun to just make her squirm a little bit.

Was it cool to finally see how you would look together, when you saw what the final dress and suit would look like?

MITCHELL: First of all, that original dress was like something out of Dark Shadows. It was Victorian gothic. I don’t know what it was. It felt like a 1970s soap opera dress. It was just wrong. Nobody was able to fess up to the fact that they felt like something was wrong with the dress. I feel bad saying that because it was actually handmade by one of our seamstresses who really is a genius. She could sew you anything. It’s a bummer that she made this thing that was universally reviled, just on a purely aesthetic level. I’m sure it was made very well. And no one had the guts to look at the other person and say, “I fucking hate this dress!” Everyone was like, “Oh, yeah, it’s nice,” with plastered smiles on their faces. I think Bree [Turner] finally said, “I’m not so sure about this dress.” Oh, no, I think it might have been someone at NBC, actually. I think one of the execs at NBC said, “We cannot use that dress!” And then, the floodgates opened. It gave them a great idea to make a thing of it. They had to write the scene where they go and get another dress. It was a win-win because they actually got some good funny stuff out of it.

With all of the things that kept coming up, all season, were you ever worried that Monroe and Rosalee wouldn’t get their wedding moment?

MITCHELL: Yeah, man! I didn’t know what was going to happen. It was awhile back when I was like, “Do you think we’re gonna actually get hitched? This is gonna happen?” Jim [Kouf] was like, “Oh, yeah, you’re gonna get married. It’s gonna happen.” But he said it in such a way where I had confidence in it, but I was also like, “They can do anything they want. God only knows what will happen.” It wouldn’t have surprised me, if the cliffhanger was that the wedding was ruined and we didn’t get to say the vows. So, it could have gone either way. We barely tied the knot before Trubel ran in with the vile and everything went to hell.

It’s been really nice to watch the relationship between Monroe and Rosalee, since it started, because they’ve become this really solid couple. What was it like to add Monroe’s parents to the mix, this season, and really have them throw a wrench into things?

MITCHELL: That was great because it causes complications. I think it’s gonna get a little more difficult. I think Monroe is going to be in for a little bit of a rough road, coming up. This last year was a little easy. My whole arc, for 22 episodes, was basically about the wedding, with a few adventures with Nick thrown in. The whole trajectory was, more or less, about the wedding. One of the writers said something to me, in passing, that gave me the impression that Monroe is going to get put through the ringer next season, a little bit. In what way, I don’t know. He said, “Did you know things are going to be very difficult for you, next season?” I was like, “I didn’t know that. I know that now.” But, there’s no details or specifics.

How was it to work with Dee Wallace and Chris Mulkey?

MITCHELL: They’re great. They’re lovely and funny. Chris has a great sense of humor, and Dee has the nicest energy on set. It was really fun. They’re both totally great, and I hope that they both come back and get to play with us more. Chris is just a sweetheart. His speech at the dining room table was a real element of his personality. He’s a sweet, funny guy. I hope that they get to come back and have more to do.

It was really fun to finally lean about how Wesen knows when someone is a Grimm.

MITCHELL: That was fun to shoot because it felt like we were harkening back to the old days, in a way, when Nick didn’t know what was going on.

Had you ever wondered about that, before that moment, or had you been told before?

MITCHELL: Yeah, we talked about it and were like, “How do we know exactly when?” We knew that you sensed it when you’re morphed, but we didn’t know about the eyes. So, we had talked about it, but it wasn’t anything that was a detailed element of the mythology or how the world works. We just knew that, if you’re in a state of distress and you’re morphed and you look, then you’ll know that it’s a Grimm, but you don’t know it unless you’re morphed. But as soon as I say that, I feel like I don’t know that, if you went backwards through time, that it would always stay consistent to that truth.

What was it like add another Grimm to the mix, with as disruptive as Trubel is, and how she knows even less about what it means to be a Grimm then Nick did?

MITCHELL: That’s totally awesome. It lends this fantastic dynamic. Nick gets to be the teacher. You realize that these writers are basically really ballsy, and they’ll do anything that will complicate things in a way that you wouldn’t actually think you could get around. They’ll just do anything. Obviously, they’ve thought it out, but they manage to be very, very surprising. Adding a second Grimm is something that people might have pondered the notion of. I’m sure people out there thought, “Is he the last one? There must be some other one, somewhere.” But just the idea of how they did it, I think they’re really good at storytelling. They’re really good at weaving a story that has a lot of unexpected elements.

Do you think that no longer being a Grimm, for however long that might last, will affect Nick, and the friendship between Nick and Monroe?

MITCHELL: I do, but it might not be in a bad way. I haven’t even thought about this at all yet. Was is it gonna mean for Nick to be a normie? It might mean that Monroe has to take a bigger role and help him. He’s basically defenseless. He’s not gonna know who the real bad guys are, that might be coming after him. It will be like he’s blind. It’s like a cat having their claws taken out.

Grimm will return for Season 4 on NBC, in the fall.