Happy Valley: How will the show end? All the theories and burning questions ahead of the last ever episode

"In this trouble town, troubles are found." We’ll hear Jake Bugg’s Trouble Town one final time for the opening credits of Happy Valley on Sunday night.

Over nine years, three seasons and 18 episodes, Sally Wainwright has told the intertwined stories of straight-talking hero Sgt Catherine Cawood and despicable villain Tommy Lee Royce, set within the stunning backdrop of the Calder Valley and its murky criminal underworld.

Wainwright had always planned for the show to be a trilogy and insists this season will "definitely" be the last. But after five twist-filled episodes, there are lots of burning questions we need answering in the last 70 minutes.

We’ve rounded up all the important questions and the best fan theories about how it will all get wrapped up for Catherine, Tommy and Ryan in the show’s finale...

1. Tommy Lee Royce will die

If the series is going to wrap up and not leave Sally Wainwright facing down questions about a season 4 for the rest of her life, it feels like either Catherine or Tommy will have to meet their maker.

With Catherine, Clare, Richard, Ryan, Ann, Nevison, beetroot chopper Surroje, the Knezevics and the whole of West Yorkshire police all having strong motives to take down Tommy, it feels like he’s got the odds stacked against him to make it onto a beach in Marbella.

One popular theory at the moment is that Tommy will attack Nevison’s posh farmhouse and it will end up burning down (check out the smoking building in the key artwork above). Perhaps Tommy will be the one who doesn’t make it out of the building?

The more pertinent question about Tommy is not about his survival or escape, its about who he takes down with him…

2. Catherine Cawood will die

She’s got two days left in the office and then she heads off to the Himalayas for some peace and quiet. We hope.

Tommy Lee Royce isn’t going to go down without a fight and he’s already admitted that it means more to him to get revenge than getting a tan in Marbs. Ryan and his freedom and secondary, because the only thing he really cares about is pulling the trigger on Catherine.

Will Catherine bow out saving Ryan, or another family member, from Tommy’s clutches. Or could both Tommy and Catherine be bumped off by the Knezevics for knowing too much?

3. Richard or Clare will die

A third option is that Catherine and Tommy will survive and that another member of the family will die in a dramatic final showdown.

Clare will be looking for a way to make amends with her sister after their heartbreaking row this week? Will she sacrifice herself to try stop Tommy and make good with Catherine?

Or is Catherine’s ex Richard in danger of becoming the show’s final victim?  The local journalist has been looking for a national scoop on the Knezevics to bring them down. Has that placed him in the line of fire in the final episode?

4. Ryan’s choice – nature or nurture

At the heart of Happy Valley has been the question of nature v nurture and whether Ryan can escape his father’s shadow. Is he doomed to follow in his dad’s twisted and narcissistic footsteps? Or has Catherine’s love and protection helped the young lad build a brighter future.

Ryan’s conversation with Tommy via the computer game chat dangled some intriguing clues about the teenager’s current state of mind as he sidestepped questions about “love”, keeping his cards close to his chest.

If the episode comes down to Ryan choosing to save Tommy or his granny, we’re confident that he’ll make the right decision.

5. The Nurse Jackie theory

Sally Wainwright has revealed that HBO series Nurse Jackie was her inspiration for writing Happy Valley and creating the Catherine Cawood character.

Nurse Jackie’s final episode had a similar ‘last day at the office’ vibe, which could be an inspiration for how Happy Valley will bow out.

We won’t spoil how the HBO drama concluded, but it was an ambiguous ending that could be mirrored in Cawood’s final shift for WYP.

6. The Land Rover theory

The richness of Sally Wainwright’s scripts means that what could easily have been a throwaway line about “double de-clutching” a car is now being picked over by fans as a possible clue to the show’s ending.

Alison Garrs – the farmer in the beanie hat who shot her son in season 2 – has been working on Catherine’s Defender ahead of her road trip. And they are the only two who know that there is a problem with getting the car started.

Will the Defender’s clutch issues prevent an escape plan for Tommy? Or are we all just overthinking this.

7. The Alison theory

Alison has already told Catherine that she would do anything to help her out. The pair have struck up a strong bond in season 3, their shared misery and heartbreak gluing the two women together.

Which means many viewers believe Alison will have a crucial role to play in Tommy’s downfall. Handy with a shotgun and a car engine, will she be the thorn in the psycho criminal’s side?

8. The Nevison Gallagher Majorca theory – DEBUNKED

George Costigan’s Nevison has been in the background for much of season 3, only cameoing to pour out the wine and show off his fancy country house. The hints of a romance between Nev and Catherine haven’t caught fire and it feels unlikely he’ll have a crucial role to play in the final episode.

Tommy’s plan to escape to Malaga and then Marbella, did trigger one wild theory that connected Nev and the Knezevic clan. But that appears to have come about from viewers mishearing the location of Nev’s holiday home – Clare said it was in Majorca.

A Happy Valley spin-off in Spain? This feels like one wild theory we can debunk.

9. Who will go down for Joanna Hepworth’s murder? Faisal or Rob?

Rob looked like he was doomed last week, but the investigation into the source of the Temazepam might save him from being sent down for Joanna’s murder.

If Faisal gets inserted into the investigation, either through his car crash with Rob, the drug wrappers or Knezevic lackeys Ivan and Matja, his DNA is likely to be all over the body and Hepworth house.

Faisal is a wet weasel and unlikely to last longer than a minute under any serious scrutiny. And he could take Rob down with him, pointing the finger at the PE teacher as a violent abuser, costing him his kids and career.

10.  Will poor Poppy finally take off her coat?

Joana’s youngest daughter has been suffering in silence throughout the series, clinging on to her puffer jacket at all times. Whether it is hiding bruises from Rob or it just acts as a comfort blanket remains to be seen.

Hopefully the Hepworth girls will move in with Jo's parents in the final episode and she can finally unzip.

11. The Knezevic theory

The conversation between Darius and Tommy in the van was notable for its may silences and awkward looks. Tommy seethed at Darius mocking him for never leaving the country. And Darius left some menacing silences when Tommy refused to heed his advice on leaving Catherine alone.

If any criminal is likely to worm his way out of this series scot-free, the slimy gangster feels like he could be the one to prove that system is broken and corrupted by money.

Maybe he’ll decide that Tommy is too much of a risk to his personal empire and tidy up business with a cement block and a reservoir.

12.  Will Ivan make his wedding?

Don’t pretend you haven’t been thinking about it? The blundering bad boy is in way over his head with Darius and had now nicked a load of cash with his mate Matja.

Catherine handed the duo’s information over to the investigating team, so it feels like it’s just a matter of whether Ivan can tie the knot before the long arm of the law catches up with him. Or a very angry Darius.

13. Who gave Ryan the first letter from Tommy outside school?

Clare revealed earlier in the series that Ryan got his first letter from Tommy handed to him outside school by a mystery figure.

Will their identity be revealed in the closing episode? Maybe it was Darius or one of his cronies?

14. Will we ever see Miss Oates

"Did you get your oats this morning sir?"

Was Rob Hepworth really have an affair with another teacher at Ryan’s school? Will we ever get to see the famous Miss Oates?

There’s only 70 minutes in the finale, so we may have to let this one slide.

15. What will Joyce get Catherine as a leaving present?

Poor old Joyce has suffered Catherine’s tongue lashings at work more than anyone else and now she’s got to decide what to buy her as a work leaving gift. We’re just keeping our fingers crossed Catherine will still be alive to receive the present and clock out of the office one final time.

16. Why didn’t Darius turn up to the hotel meeting with Richard?

Was this just a cunning red herring form Sally Wainwright in episode 5 to stress us out and make us believe either Richard was getting killed or Ryan was getting kidnapped? Or will there be more to come from Richard’s plans to expose Darius as the Knezevics to the world?

Do the Knezevics now have eyes on Richard? Did they follow him back to find out whether Catherine and Ryan are staying? Or is this another case of us over-thinking the final episode?

17. The Line of Duty theory

Tommy gets caught. Ryan gets a hug off his gran. Catherine and Clare make up. And just as Catherine is about to finish her last day in the offce, she gets a call. It's Ted Hastings on the phone - he's got one last job for Sgt Cawood... and the BBC announce Line of Duty season 7! We can dream.

Watch the Happy Valley finale on Sunday at 9pm on BBC One and BBC iPlayer