Michelle Dockery in TNT's "Good Behavior." (Brownie Harris/TNT)
TV critic

Who can’t relate to this pickle? You’re an icily beautiful actress who spent six seasons in a gorgeous English castle wearing one fabulous 1920s frock after another in a hit series in which your character’s most memorable scenes were the ones spent insulting her not-quite-as-elegant sister. Your character becomes so popular that there’s a Twitter account that pretends to be authored by her eyebrows. The series ends and you beg your agent: Get me outta here. Something, anything, so long as it’s completely different and doesn’t involve full-length gloves.

And so Michelle Dockery’s wish is fully granted, in an astonishing career swerve from “Downton Abbey” to TNT’s intriguing and impressively seedy crime drama “Good Behavior,” the first two episodes of which premiere Tuesday.

Dockery throws herself into the role of Letty Raines — a liar, thief and ex-con in North Carolina who sweats long shifts as a waitress and relies on a pleasant-voiced motivational app to keep her off drugs and booze, in between visits with her parole officer (Terry Kinney). Letty is barely hanging onto sobriety, hoping to regain the right to visit her 10-year-old son, who lives under the protective watch of Letty’s mother (Lusia Strus).

Desperate to raise the sort of cash that will get her back on her feet, Letty commits a quick string of burglaries at a luxury hotel, during which she overhears a muy guapo hit man, Javier (Juan Diego Botto), making final arrangements to murder a client’s wife. Struggling to be a better person, Letty decides she doesn’t need the death of a stranger on her conscience, so she intervenes.

You mean she calls the cops?

Gosh, no — it’s television. She disguises herself as a sexy teacher, seduces Javier, then plans to help the intended victim escape.

The true accomplishment of “Good Behavior,” created by Chad Hodge and Blake Crouch (based on Crouch’s novel), is that none of this seems as hokey as it sounds. Dockery digs deep and gives a frenetic and often moving performance, clearly relishing the chance to play a damaged and unpredictable (and poor!) person, who, despite her fears of being sent back to prison, would fit in nicely among the general population at “Orange Is the New Black,” should it come to that.

It’s no surprise that TV viewers frequently have trouble accepting their favorite actors in new parts. But actors understandably crave variety and challenges in their careers; also they need to stay employed. Despite that, it’s still hard for fans to let go, especially when it involves a character as memorable as Lady Mary, but Dockery so ably demonstrates versatility here that the least you can do is submit to “Good Behavior” long enough to get hooked. (That only took me two episodes.)

Letty’s attempt to do right goes awry and, before she knows it, she’s been abducted by Javier and forced to join him on his next hit job, where she must pose as his wife and share his bed. As distastefully abusive as that premise seems, an undeniable chemical spark occurs between Dockery and Botto — enough to propel “Good Behavior” past the glut of stylish but mediocre cable dramas that feature morally ambiguous protagonists.

The show also has an uncommon obsession with nailing some small details that, in other shows, tend to inhibit plausibility. Example: On the lam in a stolen Tesla with two bodies in the trunk, Letty and Javier spend a good part of one episode dealing with such issues as lousy smartphone reception and the car’s dead-giveaway GPS tracking, to say nothing of the lack of EV charging stations on Southern back roads. Other shows take modern technology for granted, employing it where narratively convenient, but rarely stopping to consider its shortcomings as an accomplice. “Good Behavior” gets points here for turning product placement into a crisis.

It’s one problem after another for these two, and there’s something enjoyably twisted and confident about the way “Good Behavior” unfolds as something better than a madcap crime spree or a shallow action-romance caper. Without fully condoning her sins (or her attempt to sustain an American accent), it’s fair to suggest that Lady Mary has finally found the right man.

Good Behavior (two hours) premieres Tuesday at 9 p.m. on TNT.