Happy Valley is back, and fans have two big questions preying on their minds: is Ryan (Rhys Connah) really going to take after his criminal father? And who the hell has been taking the impressionable teenager to visit Tommy Lee Royce (James Norton) in prison?

Well, the fan theories are already circulating – and nobody seems to think that Sergeant Catherine Cawood (Sarah Lancashire) is in for a happy ending.

As longtime viewers of the BBC series will already be aware, Ryan was conceived when Catherine’s daughter, Becky (Elly Colvin) was raped by her abuser. Despite finding it hard to look at the boy at first, Catherine took him in and raised him after his father, Royce, was sent to prison for murder, and his mother died by suicide shortly after he was born.

Naturally, Ryan has been curious about his father – even after Royce doused the little boy in petrol and threatened to set him alight in front of his grandmother. Catherine, however, has always been reluctant to tell him much about her arch-nemesis, and has repeatedly forbidden her grandson from ever making contact with Royce, largely because she fears he will take after his father, despite all of her efforts to raise him well.

Fast forward to series three and it seems Ryan has secretly been visiting Royce in prison ever since he began writing to his father in series two. Indeed, his father’s influence can already be felt in the language that the angsty teen – prone to unexpected flashes of anger – uses to describe his abusive PE teacher, noting that “revenge is a dish best served cold”.

Catherine learns about the visits when Mike Taylor (Rick Warden), her inspector, tells her he’s received a phone call from a prison liaison officer in Dewsbury.

“She was at this conference in Reading last week, week before, with a load of PLOs,” he shares. “Apparently someone said to her that someone else had said to them ‘that Catherine Cawood must be getting soft, letting her grandson go visiting Tommy Lee Royce’.”

“Did she say anything else?” asks Catherine.

It is at this point that Mike reveals the PLO says Ryan was accompanied by “a man and a woman”.

“He’d have to be – any kid would have to be if they’re under 18.”

Who is taking Ryan to visit Royce in prison?

The episode ended on something of a cliffhanger (obviously) as Mike reveals that he’s received some intel from Sheffield prison, where Royce is currently incarcerated – but swiftly adds that Catherine isn’t going to like what she hears (also obviously). Which, you guessed it, has prompted viewers to assume that the couple taking Ryan to visit Royce is someone much closer to home than she previously thought.

Someone like… her sister Clare (Siobhan Finneran). As in, yes, the same sister that we saw Catherine laughing with so freely at the beginning of the episode. Who has always stuck by Catherine, through thick and thin. And who has… ooh, been taking Ryan out to kick a ball around while Catherine’s been working? Sounds a bit suss to us.

“She just wouldn’t,” says Catherine at one point. “She wouldn’t do that to me… would she?”

Well, she might. Sure, Clare’s motivations for such a betrayal remain unclear – perhaps she’s just doing what she thinks is best for Ryan – but there’s no denying that she is probably the person that Catherine trusts more than anyone, meaning she could probably pull this off without being suspected.

Then there’s Neil (Con O’Neill), who has been accompanying Clare and Ryan on their alleged football outings.

“I don’t know about Neil,” says Catherine. “I’ve never been sure about Neil.”

Hard same, especially as all we really know about Neil is this: he’s Clare’s friend-turned-live-in-lover, and he – just like Catherine’s sister – has his own demons, as he’s struggled with addiction over the years.

Other than that, he’s a bit of an enigma; we don’t know if his path has ever crossed Royce’s. But if he is involved in this, one has to wonder if he and Clare are working together… or whether he’s doing it behind her back, too?

Will Ryan fall foul of Happy Valley’s long-running nature vs nurture debate?

Plenty of people have pointed out that three faces are prominent on the poster for Happy Valley’s third and final season: Catherine, Royce and Ryan – which suggests that we’re speeding towards a dramatic showdown between the trio, particularly when you combine it with recent comments by Rhys Connah.

Connah, who plays Ryan, told the BBC: “There’s more of a tension in [series three] as Catherine sees more of Ryan’s dad in Ryan, more than she’d like to see.

“Ryan has a confusing relationship with Tommy because obviously, Tommy tried to kill him… But then he’s heard all this stuff saying ‘Oh, he was sick’, so he’s questioning what Tommy is.

“He hears all this stuff about Tommy, about how he was a psychopath, a murderer, but Ryan’s now at a stage where he wants to judge for himself, as there’s enough doubt there, and of course he wants his dad to be a good man so he wants to believe things are different now.”

Creator Sally Wainwright added: “I waited six years because I wanted to get to a point where Ryan would be old enough to start making choices about whether he wanted to have a relationship with his dad or not. And could he have a relationship with his dad, and how would Catherine feel about that?

“I really wanted to be able to explore that. He is now 16, so he can travel places by himself, he can make choices. He can do things behind Catherine’s back.”

Hmm. All in all, it doesn’t look good for the Cawood family – but, then again, all of this drama could be resolved by the time the credits roll on the final episode to ensure that the eponymous valley of the title really is a happy one.

Only time will tell…

Happy Valley season three continues on BBC1 on Sundays at 9pm

Images: BBC/Lookout Point/Matt Squire