'Limitless' Preview: What Happens When Other Agents Take NZT Pills?

In the cleverly titled “This Is Your Brian on Drugs” — tonight’s fall finale of CBS’s Limitless — the focus isn’t on what NZT does to Brian Finch’s brain… it’s on what happens when a whole batch of NZT pills goes missing, thanks to a bit of pilfering by Agent Casey Rooks’s SWAT team.

Rooks (Desmond Harrington) and his squad are called upon to help recover stolen goods, which has become an FBI case because the swiped goodies includes a stash of NZT. When one of Rooks’s men decides to take several dozen pills so the team can experience the pills’ effects, Rooks — in a vulnerable frame of mind thanks to recent developments in his relationship with Rebecca (Jennifer Carpenter) — decides to go along with the experiment, and the results are… well, there’s really no better word than disastrous to describe them.

Harrington, who signed on for the show after his friend and Dexter on-screen love interest Carpenter texted him asking if he’d be interested in co-starring with her again, tells Yahoo TV he doesn’t think this is Rooks’s first time breaking the rules.

“There were some scenes from the beginning [of the season] where you can see [Rooks’s] interest in the NZT and an interest in what exactly is making Brian tick,” says the actor, who TV fans also know for his memorable performances as Jack Bass on Gossip Girl and Fletcher “The Ice Pick” Nix on Justified. “And you get the sense that he’s skimmed off the top before. … I feel like he kind of loses this relationship, and wants to know what this pill will do. So it’s kind of like, ‘Well, that’s over… let’s see what this does!’”

Meanwhile, as previewed in the exclusive clip above, the case also leads to an eye-opening experience for Brian (Jake McDorman), who realizes his fun and games with his minders, Mike (Michael James Shaw) and Ike (Tom Degnan), aren’t nearly as much fun for them.

Limitless airs Tuesdays at 10 p.m. on CBS.