'MacGyver': Lucas Till Says Season 4 Is 'Firing on All Cylinders' -- Watch the Opening Scene! (Exclusive)

The actor previews the upcoming season with ET. Plus, check out an exclusive sneak peek from Friday's premiere.

A lot has changed on CBS' MacGyver. 

Eighteen months have passed since the Phoenix Foundation was dismantled and the team, led by the uber-resourceful Angus "Mac" MacGyver, was forced to abandon their secret agent statuses for boring, ordinary day jobs. For Mac, that means teaching a chemistry class at a local university, which is exactly where he finds himself in the season four premiere.

"Everybody is broken up because the Phoenix is dissolved and none of us have really been in contact that much over the last 18 months," MacGyver star Lucas Till tells ET as he sets the table for the new season, adding that things aren't looking good for Mac and his father (Tate Donovan) or his ladylove and fellow colleague, Desi (Levy Tran). 

It doesn't take a rocket scientist to surmise that Mac is desperately lacking motivation and, as Till puts it, is "uninspired" in his new reality, as one can see in ET's exclusive sneak peek of season four's opening scene (watch above). But as the season progresses, the former operative matures in significant ways.

"You see Mac grow up in his way of thinking," says Till, 29. "'You can't save everybody,' is what part of the season turns into and it's not just black and white. There's not just good and bad, and that's what the season becomes in the first 13."

Till also previewed the addition of new series regular Henry Ian Cusick, who plays Russ Taylor, a wealthy ex-MI6 Agent-turned-private military contractor with a shady past, who comes into the picture when he hires Mac and the team for a high-risk mission. Mac and Russ, Till reveals, have a complicated relationship, to put it lightly.

"You'll see Russ and Mac butt heads, be friends, come to agreeances, fight like an old married couple at points and then have each other's backs," he says, before praising Cusick's work so far. "He's done killer backstory stuff. He's just knocked them out of the park and so does everyone else."

But what about Mac and Desi's romantic future? Is there hope for the former couple to reconcile?

"I'm about to shoot an episode coming up where their relationship is very funny. It's really, really good how they bounce off of each other and it's so easy to work with [Levy]," Till hints. "Personally, I would love to have that continue because it's really nice to getting to work with her every day."

Though Till is in the thick of production -- they're two-thirds of the way through already -- he offered up some of his favorite upcoming arcs of the season, specifically calling out episode 13, which they treated as a season finale. "There is definitely an end to a storyline," he says coyly. 

"Episode seven is a date night episode and it's hilarious," Till promises, adding that that particular hour falls just before "things start to take a darker turn... and we do stuff we've never done on this show before. I can't tell you what that is because there are a lot of surprises."

Overall, Till characterizes season four as being "better," and looks and feels "more mature."

"The beats, we hit them," he says. "Everyone's firing on all cylinders. We have all kinds of new stuff, but at the same time, it doesn't really take anything away from the people who would have loved it before. It's still a family show but just a little better."

MacGyver premieres Friday, Feb. 7 at 8 p.m. ET/PT on CBS.

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