In a busy career, Sophie Rundle will always have a special place in her heart for Monday’s BritBox murder mystery series “After the Flood.”

As Joanna “Jo” Marshall, a rookie cop hoping to make detective, Rundle, 36, is introduced in overflowing flood waters, desperately trying to save an infant from being swept downstream.

Jo is not only nearly drowning, she’s pregnant.  And once filming ended, Rundle, in a Zoom interview from London, noted how fiction begat fact — she is pregnant with her second child.

“Flood,” she found, was easy to wade into.  “It made me laugh when I opened the script and it says there’s a flood and then your character jumps right in! I thought, I haven’t done that before.

“Also, I was intrigued by how they were going to film all this. It’s one thing to say, ‘The street is flooded and they’re waist deep in the water.’ But how do they do that?

“And I was compelled by her as a protagonist. It’s such an interesting thing to have your protagonist in a procedural drama like this be pregnant. What does that look like? We’re not used to seeing that.”

Once the flood recedes, multiple troubles bubble to the surface with Jo uncovering a body that only looks as if it drowned.

The reality is, she said, “Somebody’s been murdered, somebody has done it” and it’s Jo who remains determined to find the killer.

“Along with all that, we’re drawing in the conversation about climate change. It’s touchy ground because climate change is such an enormous subject. How do you do it in a way that isn’t browbeating people?

“What’s clever about the show is that it distills it down to the impact of climate change on a small community. One that you totally recognize — and might be one that you live in. That’s quit interesting. This is what’s happening in people’s lives, and people’s lives are being ruined by it — what does that look like?

“Thread in an exciting murder mystery with a great protagonist leading you through and that, hopefully, is a recipe for a really good fun piece of entertainment.”

One that shows the stresses Jo faces in the police force, beginning at home. She is a cop’s daughter, married to a cop who only wants her to have her baby, leave the force and stop worrying about solving this homicide.

“That’s probably common for a lot of women in a very male-dominated environment, but even more so for pregnant women. There’s a lot of people telling her to just stop pulling at the tiger’s tail. Sit down, shut up. Go and have your baby. She’s just not going to do that.”

“After the Flood” streams 2 episodes on BritBox each Monday beginning May 13