We often end up having a lifelong uncomplicated relationship with siblings. They are usually the best forever-and-a-day friends, even though there are messy moments. For example, when four siblings get together to watch the back of the fifth to the point they plot the murder of number five’s husband just to save her from a messy marriage. That’s what happens on the new Apple TV+ series, Bad Sisters.

The gloriously dark, twisted sibling drama has one of the best scripts of the year — irreverent to a great degree — that reminds one of the wicked heart of the British version of the movie Death At A Funeral.

Here sororal bonding verges on drinking and plotting. JP Williams (played by Claes Bang) has no respect for women or his wife but, at the same time, he wants to remain married so that his wardrobe and meals are taken care of. His wife Grace (played by Anne-Marie Duff) doesn’t protest. In fact, she always tries to find something good in JP.

It doesn’t go down well with her sisters… the Garvey sisters who stuck through thick and thin during their difficult childhood. Eva (Sharon Horgan) is the matriarch of the clan. Then there is Bibi (Sarah Greene), who leads a stable domestic life but loses her cool now and then because of an accident that left her with one eye. She is followed by Ursula (Eva Birthistle), a nurse who is married to a paramedic. The youngest is Becka (Eve Hewson), the free-spirited youngest sister. Their objective? Save their sister Grace from her abusive marriage.

Their bond is tested when a clammy insurance broker (Thomas Claffin played by Brian Gleeson) tries to play detective to find evidence that might spare him from having to pay towards JP’s life policy.

“Writing is very important, but the next thing is casting. I could sort of see the sisters in my head. They brought so much extra to the table that you ended up your rewrites weaving their interpretation of the characters, like Ursula ended up being much funnier on screen than she was on the page. Sarah did such a deadpan with Bibi. The same with Anne-Marie and her character Grace,” says Sharon Horgan, who has developed (with Sharon Horgan and Dave Finkel) the English version of the series based on the Flemish show called Clan, during a video chat organised by Apple TV+.

Most of the series is in the form of flashback because the very first scenes show JP in the coffin. The urge to bump off JP comes to the fore after a Christmas dinner where Grace is humiliated but at the same time she is manipulated to feel secure. What follows is whisky-induced homicidal plotting.

Sharon Horgan in Bad Sisters. She has also written the screenplay for the show

‘Not just a sister’

“All our relationships are complex, our relationship with each other or relationship with partners or other family members. And that’s what makes it really exciting and interesting to play and to watch. Because it’s just a huge amount of matter to sink your teeth into. You’ve got layers to go through, understand and then bring to life,” says Eva Birthistle.

Sarah Green cuts in to say that much of the show’s success needs to be attributed to Sharon’s writing skills. She says, “I think Sharon has written an amazing group of complex women who love each other deeply and would do anything for each other, including kill. So that’s quite complex.”

For Sharon it wasn’t the easiest of tasks when it came to moulding her own character, Eva, who is the head of the sisters. “I think the hardest thing was just to remind myself all the time that I needed my character (Eva) to be motherly. It’s not always what I kind of wanted to do in the scenes. She’s not just a sister but also a mother-like figure. It was super complex. It was like, ‘Go kill a man but be careful on the way. Don’t trip over’,” says Sharon.

For some viewers, Bad Sisters will come across as too dark a comedy but for most, while for some it will be too comedic a show to skip. And both sides will agree that the theme of the show is of relevance — tackling domestic violence. Equally interesting is the way the sisters bond. “A lot happens over 10 episodes, and a lot happens to the sisters’ relationship as well. So it kind of felt like something that was constantly moving; there were these relationship dynamics that stayed like until the end of episode 10. There are huge shifts, not just to the characters themselves, but to the relationships within the family” says Sharon.

Claes Bang plays JP Williams, the mean guy who brings the sisters together

‘Murder ballet’

Even the main song of the show has been chosen well — PJ Harvey’s version of Leonard Cohen’s Who By Fire. “I just had the idea that we should do a cover of Who By Fire, a Leonard Cohen song, because it speaks of death and here on the show there is the matter of killing someone. I then had the idea of getting Polly Harvey (better known as PJ Harvey) to cover it. I felt there should be something of a ‘murder ballet’ kind of vibe to it. We just went looking for murder ballads. Ultimately, it’s a mixture of original tracks and composition,” says Sharon.

The script is so tight that it will be almost impossible for you to wait for a week for a new episode to arrive. Excellently paced and brilliantly performed, everyone has an equal share of the spotlight.

“I think it was really easy for us to play sisters; it came very naturally. I think Sharon had written really authentic relationships. So it was really easy for us to kind of inhabit those roles and feel like sisters. We felt as a group of actors working together, like allies from the very start, looking out for each other. We had a period of rehearsals where we got to know each other even better. What I love about them is that they love one another but are also frustrated with one another; it’s not quite hate but really complex emotions. It feels very honest,” says Sarah.

To get into the groove, Sharon visited Forty Foot, a promontory on the southern tip of Dublin Bay. “It was chaotic in the best possible way. And it was incredibly cold. It was a pretty bad time in way of weather but people in their 90s were pouring in and like laughing at us sitting in the corner. I had such a gorgeous experience. When I was getting ready to write the script, a part of the research was to go in there and just get a handle on the place and I went there with my sister. We got into the water and we just noticed that loads of female friends would be in the water, swimming and chatting… just catching up. And it just felt like a great place to make murder plans. It also felt like a great place for camaraderie,” says Sharon.

The mix of chaos and camaraderie helped Sharon to etch the most memorable characters we have seen on screen in a long time — JP, whose every word is coated in sarcasm and then double dipped in dishonesty. Claes Bang had earlier told The Telegraph that he didn’t really have to try too hard to play the mean guy, sort of a cartoonish villain. Ultimately it is his character’s mean streak that brings the sisters together and form a bond that lasts forever.