Daisy Haggard is the first to admit her British import, “Back to Life,” doesn’t sound like a comedy — or at least what Americans think of when it comes to funny stuff.

The series, premiering Sunday night at 10 on Showtime after a six-week run on the BBC in April, follows the return of Miranda “Miri” Matteson to her parents’ home after 18 years in prison. The crime — a murder — rocked the sleepy coastal town where she grew up. (The show was filmed in the southeastern Kentish seaside town of Hythe.) Haggard, 41, describes Miri as “an adult beginner with a terrible past.”

Re-entry into her new life runs the gamut from awkward to humiliating: posters of David Bowie, George Michael and Prince on the walls of her old bedroom remind Miri how much life she’s missed. Her ex-boyfriend has married and started a family. Local vandals spray-paint insults on the garden wall on her parents’ home. As for her parents, they have their guard up, too: Mom (Geraldine James) has hidden the kitchen knives.

“By putting a woman in her late 30s back in her hometown where she’s got no job, no friends, and a town that hates her, we thought it presented the most number of challenges,” says Haggard, who is married with two children. “Extremes are quite fun, aren’t they?”

Haggard’s open face, broad smile and bright blue eyes keep you wondering how Miri could have gone so wrong. But one by one, she wins people over. She gets a job at a fish and chips shop (“Everyone deserves a second chance, even murderers,” says her interviewer) and makes friends with a neighbor (Adeel Akhtar) who “makes her feel normal.”

“I am a relentless optimist who, every time I fall down, I get back up again, keep on trying,” says Haggard, who co-wrote episodes with a newborn baby on her lap. “So I suppose [Miri] shares my sort of hope. It meant that I could bring the lightness to the part when it was needed.”

After “Fleabag” swept the Emmys in September, imported series that are comedies with a dramatic edge stand a better chance of finding a TV home; it’s no coincidence that “Back to Life” comes from the same production company that gave us the Phoebe Waller-Bridge hit. Haggard says the British run of the show prompted a positive response from viewers who felt like they were outsiders, and from former prisoners themselves. Says show writer Laura Solon, “British humor is more about pain and suffering. American humor is more joyful, upbeat, can be very ironic.”

Or to put it another way: “Maybe we are quite mean in Britain,” says Haggard. “We love watching people struggle.”