It took me about 1.5 new episodes of “The Flight Attendant” to remember exactly how stressful it is to watch “The Flight Attendant.” It had been long enough since its November 2020 premiere that my memory of the show had almost become a facsimile of its slick Saul Bass-ian credits, in which a tiny blonde flight attendant runs away from shady spies and enormous bunnies. I knew I loved Kaley Cuoco’s screwball energy, Michiel Huisman’s arched eyebrow, Michelle Gomez’s exasperated sigh, and the dueling pleasures of a skittish Rosie Perez and a ruthless Zosia Mamet. Diving into the second season, though, provides a forceful reminder of just how good this show is at getting you inside the head of someone constantly on the edge of a panic attack.

Cassie (Cuoco), of course, would vehemently deny this characterization. The season’s first two episodes, which premiere April 20 on HBO Max, pick up almost a year after the Season 1 finale, which ended with Cassie taking a part-time job at the CIA and committing to getting sober. Both decisions have equally huge implications on her life and, as quickly becomes clear in Season 2, represent conflicting sides of herself that she still doesn’t quite know how to reconcile.

In her public life, Cassie’s more put together now than ever. She’s moved across the country to Los Angeles, 3000 miles away from the city that saw her at her messiest lows. She’s dating a handsome new man (Santiago Cabrera), who’s also sober and clearly adores her. She comes home from long flights to an adorable bungalow filled with light and houseplants, none of which are dying. It’s a picture perfect image for her to sell at the Alcoholics Anonymous meetings where she trades past horror stories with her proud sponsor Brenda (Shoreh Ashdagaloo) over donuts. After watching Cassie drunkenly stumble into one terrible decision after another in the first season, it’s undeniably moving to see her doing her damnedest to stay upright in the second.

In her secret life as a CIA asset, though, Cassie can’t (or won’t) stop defying her boring orders. Without the promise of oblivion that alcohol once gave her, Cassie keeps subconsciously finding herself chasing thrills to the point that she, once again, ends up at the center of a wild conspiracy that seems to get more dangerous by the minute. As things spiral further out of her control, Cassie retreats far enough into her own head that she ends up trading barbs with different versions of herself, including a frustrated party girl, a depressed drunk, and the tween girl (Audrey Grace Mitchell) who had to grow up too fast. Cuoco’s proven adept at navigating the hairpin turns in tone that “The Flight Attendant” can take, and the same holds true for her depictions of each new Cassie that ends up haunting the show.

The combination of dramatic music stings, near-manic editing, sharp cuts to fragmented flashbacks, and warped trips into Cassie’s headspace can make for a genuinely nerve-racking viewing experience. (By Episode 3, I was anxious enough to abandon my office chair so I could watch the show while furiously pedaling on a stationary bike — a choice I cannot fully recommend unless you’re craving a serious workout.) As the second season sets up a complex web of overlapping stories, making frequent use of its signature split screens to illustrate exactly how they’re all unfolding, it can all feel just as scattered as the inside of Cassie’s brain.

But that, it seems, is at least half the point of “The Flight Attendant,” which is as much of a character study as it is a spy thriller. For all the solid supporting performances and fresh intrigue around every corner, this show is about how Cassie — and, by extension, Cuoco — will handle what it throws at her. Making viewers live on the knife’s edge alongside her every fraught choice can be exhausting, but it’s also what “The Flight Attendant” does best.

The first two episodes of “The Flight Attendant” Season 2 premiere Thursday, April 21 on HBO Max, with two more airing each week until the finale.