Deadwater Fell writer explains ending to David Tennant drama

When foul play is detected, Tom becomes the prime suspect as the only survivor, leaving friends Jess (Cush Jumbo) and Steve (Matthew McNulty) to question everything they thought they knew about him and his late wife, Kate (Anna Madeley).

Back in 2020, when the show had its initial broadcast, RadioTimes.com sat down with screenwriter Daisy Coulam (of Grantchester fame) for a spoiler-filled discussion of the season finale.

Read on for what she had to say about the Deadwater Fell ending as well as our recap of the key moments in the episode.

Why did Tom commit the murders?

After much speculation, the final episode reveals that Tom killed his wife and three young daughters after discovering Kate's plans to divorce him.

The evidence was there from the very beginning, most notably the injection marks in his victims' arms that only a doctor could have administered so effortlessly.

As the series progressed, we saw more of Tom's relationship with Kate, which was hostile and dominated by his coercive control over her.

Writer Daisy Coulam explains that having Tom as the culprit was the plan from day one, despite viewers being suspicious of almost everyone – including Kate herself.

"I found it really interesting that people have looked everywhere. In fact, they say it’s 'too obvious' to be Tom," she told RadioTimes.com.

"I felt all along we wanted to say something about the men who commit these crimes, because it is men who are more likely to commit familicide than women.

"That’s what we wanted to talk about and it’s very interesting that people are thinking it’s a whodunnit. By the time you get to episode 3, I thought it was pretty clear that he had done it.

"And so, episode 4 sort of became an unravelling of the truth of the matter."

Coulam didn't want to include any kind of justification for Tom's awful crimes, but nor did she want to completely lose the humanity of his character.

"I was really keen not to go, 'it’s his mum’s fault’ or ‘it’s his dad’s fault'. I didn’t want to excuse him because people have terrible relationships with their parents, but that doesn’t make them coercive controllers.

She added: "When people commit crimes like this, they get called monsters or they get called evil and that to me is a way of diminishing the fact that they are humans and they committed these acts.

"So, I think Tom is a complex individual. He’s a human being who has made some terrible mistakes."

Why was Lewis self-harming?

One of the most shocking scenes in Deadwater Fell's series finale sees Steve's son, six-year-old Lewis (Bradley Connell), harming himself by picking at his burn from the first episode.

Coulam said: "For me, the last episode is all about communication and silence. If people don’t talk, then these things fester and with Lewis, he’s not been allowed to talk about the issue.

"Everyone’s been trying to keep a lid on it and not upset him, but actually, he’s expressing it the only way he knows how, which is to pick at his skin.

"Where this whole situation arises from is that men are incapable of talking about their problems and it gets bottled up. Then, the kids follow suit and in a generation’s time, we’ll have these problems still."

These issues are certainly reflected in Steve (Matthew McNulty), who doesn't physically hurt himself in the series, but suffers intense psychological pain that very nearly destroys him.

Coulam added: "Some of my favourite scenes in the series are when Steve does his counselling and even when he’s faced with an opportunity to open up and talk about his feelings, he can’t and he says ‘I feel good.’

"That then bleeds through the rest of the series; him not communicating means his son doesn’t communicate and it’s an endless cycle of toxic masculinity."

Will Steve and Jess stay together?

After some truly harrowing experiences and an extremely rocky patch in their relationship, Steve and Jess actually end the series on a relatively positive note.

As they look to leave this dark chapter of their lives behind, Coulam is optimistic about their future together.

"I think they’ve started to communicate," she said. "It’s the scene where they’re in bed together and they look at each other and they talk to each other for the first time, since even probably before the fire.

"They talk about things that are upsetting them and through that they heal. I think they’ll go on and be happy."

Why didn't the IVF work?

Throughout the series, we see Steve and Jess attempting to conceive a child through IVF, a subplot which was inspired by Coulam's own experiences with the medical procedure.

In the final episode, it is revealed that their efforts were unsuccessful and Jess is still not pregnant, but she and Steve decide that outcome is the right thing for them upon reflection.

"I don’t think I realised how low the success rate was when I went into it. You go in hopeful and you read so many hopeful stories where it works, but when it doesn’t work it’s a bit soul-destroying," Coulam said.

"So, I wanted my characters to decide not to do it and have that be a positive ending for them. I’m quite bored of reading ‘IVF didn’t work, life is over’ stories, because I don’t think life is over.

"If you don’t have kids, that doesn’t mean your life is over – you just need to find a different way."

Why didn't Carol come forward sooner?

One of the biggest reveals from the final episode is that Tom's mother, Carol (Maureen Beattie), was fairly certain of her son's crimes from the beginning.

We discover that she received a call from her son just before he started the fire, which strongly implies his involvement in the murders. Coulam reveals more about why Carol decided to withhold this vital information for so long.

"When you realise that somebody in your life is toxic, it takes an awful lot of courage to speak up and I suppose she sits into that theme of communication and openness. She needs to admit to herself that her son has done this terrible act," she explained.

"When you say things out loud, sometimes that’s the hardest thing. Basically, in that last episode, all of our characters are saying things that they’ve just been unable to say. Actually, only by doing that can you move on."

Deadwater Fell is available to stream on Channel 4 and Netflix. Sign up for Netflix from £4.99 a month. Netflix is also available on Sky Glass and Virgin Media Stream.

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