This is an archived article that was published on sltrib.com in 2016, and information in the article may be outdated. It is provided only for personal research purposes and may not be reprinted.

Michelle Dockery, who spent six seasons as Lady Mary in "Downton Abbey," returns to series television as a thief/drug addict who hooks up with a contract killer.

Good heavens, what would the dowager countess say?

Don't be shocked. It's acting.

"I was very fortunate that something so different from what I had been doing for the last six years came my way," said Dockery, who affects an American accent for the TNT series "Good Behavior," which airs its first two episodes Tuesday at 7 and 8 p.m. "It really is an amazing, amazing thing to be part of."

(It's a very adult show, rated TV-MA.)

"Good Behavior" gets off to a very strong start, and Dockery's performance is arresting. She stars as Letty Dobesh, who's definitely a bad girl. She's smart, sexy and tough, but she's also a thief and a drug addict. She's just out of prison and hoping to reconnect with her son, but that is not looking like a real possibility.

"I could talk for hours about her. She's an extraordinary character," Dockery said. "But like all of the characters in the show, they are flawed.

"I think they're the best of characters to play."

The role calls upon Dockery to play a character who herself is an actor of sorts, assuming other identities to commit her crimes.

"It's character within character, which is a dream for an actor," Dockery said.

Shortly after her release, Letty is robbing hotel rooms. And when she doesn't get out of Argentine assassin Javier's (Juan Diego Botto) room quickly enough, she overhears him accepting his latest job.

Letty steals the $50,000 Javier has just been paid, but — weirdly — goes to warn the intended victim. Which puts her in Javier's grasp and launches the series.

"It's about these two sort of lone wolves who crash into each other — this thief and this hit man," said executive producer Chris Hodge. "And it's really a totally [expletive]-up love story."

Letty and Javier are oddly compelling characters who pull viewers into the narrative.

"Javier is a guy that kills people for money, but other than that, he's a very nice guy," Botto said.

While it's very heavy material, "Good Behavior" doesn't feel weighed down.

"As much as it's dark, it can be very light," Dockery said. "It can be extremely funny."

"Like life," Hodge added.

The 10-episode first season only covers six weeks from start to finish. If the first three episodes are an indication, it's going to be a wild ride — more wild than the six-season ride Dockery went on in "Downton Abbey," perhaps.

"I've had the opportunity to play two very strong female characters, and there are some parallels with them," Dockery said. "It's just very different periods. One happens to be in the '20s and one modern day.

"But Letty, she's an extraordinary character. So colorful and raw. And she's fascinating to play.".

Scott D. Pierce covers TV for The Salt Lake Tribune. Email him at spierce@sltrib.com; follow him on Twitter @ScottDPierce.