“Bad Sisters” was a limited series, and the finale seemed to wrap everything up flawlessly.

But then writer and star Sharon Horgan decided she wasn’t done with these characters and their saga. And so Apple TV+’s critically acclaimed, darkly comedic drama is back for a second season as the Garvey sisters deal with the consequences of the first season’s murder and cover-up.

The sisters — played by Horgan, Anne-Marie Duff, Sarah Greene, Eva Birthistle and Eve Hewson — return, joined by Fiona Shaw as a nosy neighbor and Owen McDonnell as a love interest who may be too good to be true. The police are investigating a freshly discovered corpse and crimes that may land the sisters in deep trouble.

Horgan spoke recently by video about what drew her back to the story. This interview has been edited for length and clarity.

Q: The first season was so great and the ending seemed perfect. When did you decide to do a second season, which dives into the guilt and collateral damage left over? Were you wary of messing with what you’d achieved?

A: I felt then that the end was perfect as well. But I loved the cast and telling the story of these sisters and I had an idea of what could happen, which is exactly what you said about the fallout and the guilt. I’m actually really grateful to have this opportunity because it felt like a fairy-tale ending. But it wasn’t real life. And what people enjoyed about the show was that it did feel real, even though it was an extraordinary and almost ridiculous premise — it felt like real women dealing with a terrible thing.

Grace is such a good person, but she’s also damaged from years of being in that relationship and being vulnerable. You don’t just kill your husband, the man you love, the father of your child, and say “Yay” and jump into the sea. You do, but then what?

It was about telling the story of the ongoing trauma of having been in a relationship like that and the fallout from that and what happens if you, as a vulnerable person, leave yourself open to someone coming into your life who doesn’t want the best for you, and how the shame of that would stop you from turning to your family.

The fallout in this season is a direct result of her relationship and the abuse, but to me it felt way more truthful and actually way more in my ballpark of what I like to write about, which is family and relationships and looking for their truth, looking for what’s underneath.

Q: My fiancée, a psychologist who frequently deals with trauma, says the first two episodes of the new season accurately capture the trauma and post-traumatic stress disorder that Grace would have felt. But that made those episodes darker in tone. Were you conscious of that shift as you were writing?

A: We almost didn’t do it because of that. We knew the story we wanted to tell, but not how far we were going to take it, I was a little nervous. Is this going to feel like the same show? I think what people want from a second season of any show is for it to feel the same but completely different.

So if we went that dark, I wondered if we’d be able to hold onto the thing that makes it this show — the comedic drama and the irreverence of the sisters. But it felt really important to show what happens when that kind of guilt and shame get to a point where there’s just a wall and you can go nowhere.

And there’s a lot of joy as well. I went to see a screening last night and there was so much laughter until the buildup of all that emotion and then you could hear a pin drop. I feel like those moments can land so much better than in a drama with a humor void; when there’s been some comedy, then it really hits you around the head.

Q: There’s plenty of moral ambiguity here, the idea that people can be hero and victim and perpetrator, depending on the context. We love and root for the sisters yet they committed or covered up a murder; we laugh at and disdain the lead detective but there really were serious crimes committed.

A: It’s all about moral ambiguity, especially as you watch to the end. It’s about the choices we make that feed into that equation, where good people do bad or at least very questionable things.

With Season 1, there was a catharsis for people watching to be able to hate one awful character.

This time there’s the institution of the police — if you can’t trust the people who are supposed to protect you, where do you go? Yes, crimes were committed, but there are an awful lot of reasons to feel unsafe as a woman, even around the police.

That was something that just kept coming up as we were shooting the first season, and I wanted to use that.

I feel like we should all be a lot angrier about how easy it is to get away with stuff and how hard it is to punish even the bad ones. It seems like there’s just sort of excuses made for racist, sexist institutions. I wanted to shine a light on that but for it to feel like a natural part of the story.

Q: How conscious are you of balancing the plot, the character development, the humor and the larger themes?

A: It’s a nightmare. The scripts are always overly long because I do a lot of character work. That’s what drew people to the series. But the thriller has to be this propulsive thing. So anything that felt like character stuff, I’d make sure there was a way it tied into the thriller plot so if someone wanted to cut it I’d say, “That can’t go.”

Or I might get an exec note saying, “I don’t know if that’s the right place for that joke” and I would say, “Just let me try it.” It can always go in the edit.

But I do feel like there’s a gallows humor even around death which is how you are with your siblings and also when you’re trying to deal with the darkest moment in your life — terrible things are said and terribly funny things are said, and it just sort of pierces the tension, sort of gives you a little release and then it’s awful again. But those moments have to exist. They exist in life.

Q: After two seasons, do you see more of yourself in Eva? Do you see more of Eva in you?

A: I think there’s weirdly a lot more of me in her this season, and I think that’s just because in order to flesh her out and get her to a place where she’s made peace with some things and working on herself, it’s what I’d been doing in my own life.

Well, I’m never going to be as good as Eva. That’s the problem. Although I’m better than I used to be. I’m a less selfish person. I’m more aware of other people. I guess that also just comes from a lifetime of making mistakes.