It feels like The Flash has found its groove again in Season 4, and it’s been a relief for fans and for star Grant Gustin. “Yeah, it's been a lot more fun,” he told us during an interview Vancouver this week where journalists were invited to the show’s set. “I’ve talked about it some in interviews and I don’t want to make it sound like last year wasn't fun, [but] when it gets that serious all the time, it weighs on you. It's been a good time this year getting back to the feel of Season 1 and joking around and having a good time.”

In the episode “Girls Night Out,” we get to see a rare drunk Barry (“It was fun,” he said. “It was like, if we're going to get drunk, let's just be like plastered drunk. Like schwasted […]It was definitely a different side of Barry. I feel like we haven't ever seen him like that”), and some more of Hartley Sawyer’s Ralph Dibney (The Elongated Man) being a part of Team Flash. “Hartley and I started to hit it off right away, honestly,” Gustin said. “I’m sure everyone's made this connection, comparison. He's like a young Jim Carrey. Someone started to say it on set right away, just all the physical comedy stuff he can do. ”

Though Gustin said that he is missing Tom Felton as part of the cast this year, it’s nice having Sawyer as a part of the new team. That, along with Wally’s departure, has changed some of the dynamics of the team this year, but maybe the most important part of all of this is how much Barry is actually learning from his past. “I think we're seeing him mature a lot more this year,” Gustin said. I asked if that also plays into the fact that Barry isn’t (currently) using time travel to solve all of his problems, and instead, the show is focusing more on detective work:

“That's pretty on point. Also with bringing in Ralph Dibny, they have their detective background with each other. That's kind of the selling point with Ralph, why he wants to get him to work with Team Flash, he's like, "I want to teach you how to be a good detective again." There's been a lot more of that for Barry and we don't see him too much as a CSI. There's been a little bit less of the like, "Guys, what do I do?" and more of the problem solving on his own. We'll still some of the, "Guys, what do I do? I’m not fast enough!" but he's been trying to solve more problems on his own, a lot more detective work and Ralph and Barry have been doing that together a lot which has been cool. And the DeVoe storyline calls for it because we're just solving a problem from the beginning of the season on.”

Speaking of DeVoe, Gustin told us that, “The Thinker is more less about Barry and more about his vision of Central City and how he thinks he can make it better and make the world better. He doesn't really become obsessed with Barry and the team as in the way as they start to become […] He's more all knowing than any big bad we've had before. Every time we think we're ahead of him, we realize he's still three steps ahead.” He continued,

“Barry starts to get an inkling early that this is going to be somebody serious and we're going to want to nip it in the bud right away just because when we heard about this guy, thinking back to who we heard about him from: Cadabra mentioned DeVoe to Barry and then Savitar, evil Barry actually mentioned him to Barry and Iris. So Barry's taking it pretty seriously right away. He starts to, before anybody else on the team, knows for sure that this is our guy and starts to become a little bit obsessed with getting him, because he doesn't want things to get out of hand again, as they always do. We start to see him unravel slightly for the first time all season, because he's been pretty put together this year, positive. He starts to become a little obsessed with finding this guy and getting everyone to see and be on the same page as him and see that this our guy for sure. But everyone else has their doubts for a while.”

Part of DeVoe’s plan has included creating new metas. “Everyone that was on that bus is now what we start to refer to as the bus metas. You know, as we do on The Flash. Barry actually points that out at some point. He doesn't necessarily love the idea that we're just like, ‘The bus metas!’” Gustin joked. “They all have to do with his plan. None of this was an accident. We don't realize that at first but we start to see everything's connected and we don't know why he needs all these people and why he did this to them.”

But Barry is also going to start getting overly focused on the Thinker’s game, “Barry's starting to get obsessed that this is our guy, he realizes that it's going to get dirty quick, and before it gets dirty he wants to get ahead of this guy. And then they start to realize what a challenging foe he's going to be and different than any other speedsters we've faced in the past. He's not a speedster, he's something we've never seen before. Things are going to take a dark turn quickly in the middle of the year.”

As he added, “again, Barry is trying his best to mature and I think a lot of it is happening naturally so we'll see them start to butt heads. He's still Barry and he's hot-headed and when he's sure he's right, he's stubborn. But the team is in a good place this year so we're not going to see any massive hiccups with the team at this point in the season. They'll recover.”

Speaking of the team (across the entire Arrowverse), the biggest event in the first half of this season though is, of course, the crossover, which revolves around Barry and Iris’ wedding (and which has already been filmed).

“We've been leading up to this wedding for a long time. It's in some ways fitting that it's part of the crossover because it's also a little strange that we've been leading up to this wedding and it's not even on Flash, it's technically on a different show. I'm interested to see how some viewers feel about that. But it's also how this show started, on Arrow. We've consistently had these crossovers and we're bringing so many characters together for this wedding, it's kind of fitting that it happens somewhere else. [The wedding set] was in this warehouse that they built a church. It was insane. You thought you were in a real church and it was beautiful. I'm excited for everyone to see it.”

As far as the scope of the crossover this year:

“It was bigger than ever. We knew it was going to be bigger than ever too. But every year, you can't really prepare yourself. You think you're preparing yourself, knowing that the crossover is coming but it's a big thing. It's a really challenging feat. I think this year, every year, we top it. There's more people than ever included, some of the biggest sequences you'll see with the most superheroes we've ever seen together at any given time. But we stick also, at least The Flash side of things, we stick with the comedy we've had all year. That still exists within the crossover. Barry and Kara have a few interactions that are fun, and I meet a couple new characters. It's bigger than ever before.”

Finally, when it comes to Barry’s time in the Speed Force that started this season, Gustin assured us that it matters moving forward. “That was all very important, everything he said at the beginning of the year.” This house is, after all, bitchin’.

The Flash airs Tuesday nights on The CW.