Jo Marshall (Sophie Rundle)

Jo’s a woman of action; she has to be doing. She joined the police to make a difference; commitment to her community is in her blood - her dad, Brendan, was a detective. They’d talk about the cases he was working on; he said she made interesting connections - and when he died - three years ago - an overwhelming ambition to follow in his footsteps really gripped her. But it’s not an ambition her overprotective husband Pat is happy about. Jo has an extremely close relationship with her own mother Molly - and since Brendan’s death, she has looked at Mackie as a surrogate father figure. Having spent her entire life in Waterside, she knows this community inside out, and they all know her. So, when it transpires that there may be a killer among them, Jo’s commitment to solving the mystery and protecting her town is dogged and unwavering. However, although her intentions are pure, her adherence to the rules is less so - and her determination to get to the truth often gets her in more trouble than she anticipated.

Phil Mackie (Nicholas Gleaves)

Phil was born and bred in Waterside, and was best friends with Jo’s dad, Brendan. Mackie is a proud and unwavering family man – a dedicated husband, a committed foster parent, and surrogate dad to Jo following Brendan’s death. He and his wife Sarah have taken in numerous children over the years, which is partly why he’s never risen above the rank of Sergeant - instead putting his focus into supporting his ever-changing family. When we meet Mackie, he’s the warm, stable leader of the community, taking charge in the wake of the devastating floods.

Molly Marshall (Lorraine Ashbourne)

Molly has spent her whole life in Waterside, growing up alongside Mackie, Sarah, and her late husband Brendan. Family has always been the centre of Molly’s world, but with her husband gone and Jo settled with her own family now, Molly has found herself feeling a little lost – although she’d never admit to this publicly! When we first meet her, she’s been focusing her energies on campaigning to stop the town from flooding – and has a severe axe to grind with Sarah Mackie, who she blames (along with the local council, and wider government) for a host of failures. It all feels a bit generalised though - so she’s trying to think of other ways to take action - ways which might also bring her into the orbit of Jack Radcliffe…

Lee Ellison (Jonas Armstrong)

Lee has had a painfully troubled upbringing, which saw him falling in with a bad crowd as a teenager, before eventually finding himself in a young offender’s institute when he was 16. No matter how much he’s tried to escape a life of criminality since then, he’s always been pulled back in. Despite this, there is a goodness in Lee – his heroics at the start of the series demonstrate this – and he ultimately wants to do the right thing, but by this point in his life, that simply isn’t an option anymore. When we first meet Lee, he is simply the mysterious hero that Jo develops an inexplicable connection with - but as they grow closer, his darker past soon comes to light…

Pat Holman (Matt Stokoe)

Pat’s a detective working within the Serious Crime squad, until the flood emergency brings him back into Waterside Police’s murder team. He loves his wife Jo deeply, but he’s overly protective of her - always treating her with kid gloves, wrapping her in cotton wool, and he would much prefer it if she wasn’t in the police force. Now that she’s pregnant and due to give birth in a matter of months, he’s secretly hoping that she will re-think her career as a detective, but he knows that conversation isn’t going to go down well. They do have a tender relationship, and he wants their marriage to work, but his overprotectiveness has been slowly driving a wedge between them. Ultimately, Pat is a family man through and through, and he can’t wait to be a dad. But he can sense Jo doesn’t feel quite the same way about impending parenthood, which is another point of tension in their relationship.

Deepa Das (Tripti Tripuraneni)

A junior police officer and partner to Jo, we meet Deepa in the midst of the flood emergency. She relishes her role in the police - and is jealous of Jo’s impending move into CID, with ambitions of her own to one day become a detective. As a partner, she’s fiercely loyal to Jo, but isn’t afraid to call her out on something if the situation demands it.

Jack Radcliffe (Philip Glenister)

Jack moved to Waterside 30 years ago and built a property empire from humble beginnings. Charismatic, persuasive and well-liked, Jack enjoys the status of being a big fish in the town he now calls home. When we meet him, Jack’s on the cusp of the biggest development of his career – having picked himself up from near bankruptcy, he’s turned his fortunes around and built a new, green eco-development - with plans for an expansion firmly in place. The eternal bachelor, Jack has always been partial to the chase, but not so much the commitment of relationships. Jack has a close relationship with Sarah Mackie, who’s Chair of Planning on the council. Things are going well for Jack, but when one of his buildings becomes the centre of the police investigation, Jack inevitably finds himself in the spotlight.

Sarah Mackie (Jacqueline Boatswain)

Growing up in Waterside, while Molly and Jack were always at the centre of any group, Sarah often found herself on the fringes, lacking their self-belief. But today Sarah feels, more than ever before, that she's at the centre of things. It's taken a long time, but she's where she always wanted to be. Her ambitions for herself, personally and politically, have been ignited - and she's looking to continue this trajectory by becoming a candidate for the Tories in a parliamentary by-election. Westminster is a possibility. But all of that is put at risk when the flood hits Waterside, and Sarah’s response to it comes under intense scrutiny.