Will Tommy’s thirst for vengeance be his undoing on Happy Valley?

Instead, we finish episode 5 thinking that Ryan could very well dob his father in, and also that Tommy's perfectly laid out plan will almost certainly not go that way.

Why, though? Well, on top of dealing with one of the most notorious criminals in Halifax, Tommy is also intent on carrying out one last revenge mission against Catherine (Sarah Lancashire).

It's unsurprising for us all watching but when he admits as much to Darius (Alec Secareanu), he looks at him with the kind of pity only reserved for a person that may not live to carry out their mission in the first place.

When driving him to his newfound temporary home, Darius runs Tommy through his travel plans. "He's going to sort you out with everything you need, you and the boy," he explains, but even in the way that Tommy speaks about going abroad for the first time, Darius laughs.

There's something completely childlike about Tommy, from the way he speaks to the way he acts around Ryan, almost making the pair seem as though they're both 16 years old and not father and son. It's this immature attitude around his unflinching desire to kill Catherine that may be his ultimate undoing.

Darius is aware of Tommy's "little bit of business" but double checks that it's not "that police woman". Tommy simply laughs, drinks and asks Darius if he can get him a gun.

Later on, Darius smiles and reminds Tommy: "A week from now, you'll be in Marbella – you and your boy, laughing your socks off, alright?"

Then adds: "But Tommy, this business with this policewoman. I'm going to be honest, I don't think it's a good idea. You're going to get this new life with your boy. If you fix that police woman, all sorts of s**t is going to kick in and it makes me uncomfortable.

"I think you should let it go. We've been really clever with all this, you're out. You do something crazy like that? Can't guarantee what happens."

Even when Darius's unspoken threat lingers in the air between them, Tommy just can't help but get riled up at the thought of Catherine. "Yeah but getting even with this b***h is as important as getting to Marbella."

"Is it? Really?" Darius asks slowly, even repeating the question again: "Is it really?"

And in that moment, like any great tense drama, the air between the two criminals shifts ever so slightly. Like Ryan has been known to do, Darius seems like he's pacifying Tommy in the next moments, asking him for his rundown of the revenge plan.

While both men have undoubtedly done unmistakably immoral things, Darius seems to be showing a relative sense of morality here, trying to get Tommy to think of the wider picture. Let's not think for one moment that Darius saying he "can't guarantee what happens" means he'll let the world catch up to Tommy. Oh no.

If anything, it means that Tommy could very well be in Darius's own firing line if he chooses to go against his wishes. The dynamic between them both makes for unsettling viewing, especially when they're both prone to random acts of violence. It's a weird watch, especially in the way that Tommy pesters Darius for a gun being reminiscent of a child asking for sweets.

Darius leaves Tommy with one final note, saying: "Right, well, you do what you have to do. I'm advising you not to, I'm asking you not to. But I'm not going to fall out with you, Tommy, you do what you have to do. But there's no guns."

But as Tommy leaves the van and grabs his stuff, Darius looks after him with the kind of look that can only signal that he's got other plans for the new fugitive.

Let's face it, this is a relationship that completely and solely relies on trust. Tommy has nobody right now and Darius could very well play that to his own advantage by killing Tommy, or even revealing his location to the police to further his own budding political agenda.

As outlined in season 3 episode 1, Detective Superintendent Andy Shepherd (Vincent Franklin) explained that Darius had ordered Tommy's murder in prison, which is why his face was cut up. And if pushed, we're sure Darius would order a hit on Tommy once more.

One thing's for certain: Tommy's intense hatred for Catherine has always been unfathomable and unwarranted. He's built up an image of her in his mind, rather than recognised her for all the good she's done in bringing up Ryan. When someone is that blindly angry, there's no betting on what they'll do.

We know there's going to be a face-to-face showdown between the pair and although many fans seem to think Catherine could meet her end in the finale, something tells us that the same could also be said of Tommy.

Happy Valley season 3 continues on Sunday at 9pm on BBC One and BBC iPlayer. The first two seasons are available to watch on BBC iPlayer now.

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