It's time for Law & Order: UK fans - time to put our Kleenex boxes down and face the future of our show.

When an armed robbery spins out of control into murder and a hostage situation, Ronnie and new partner Sam get the call to speak for the dead and save the living. They catch a quick break when one of the culprits turns up in the ER, but his lawyer (that's former Red Cap star Tamzin Outhwaite) demands her client gets a deal before he gives them the location of the hostage. This does not sit well with Sam, but over his objection, Sharpe gives the cops ten hours to find the hostage or he'll sign the papers. Clock's ticking, boys.

Ronnie and Sam start to dig through their suspect's life, paying visits to his mum and his girlfriend, the latter of whom informs them that he borrowed her van, and that he's still friendly with his former cellmate. They raid the cellmate's flat, but it's for naught - the suspect's lawyer has called the hostage's wife and has her breathing down Thorne's neck, so he signs the deal. When Sam and Ronnie get to the location they're given, however, they find their hostage dead. In fact, he's been dead for quite some time. They've all been played.

Not one to take this lying down, Thorne reneges on the plea deal and intends to put the screws to their culprit. It won't be easy, though, as none of the witnesses can make a positive ID, and our heroes find the corpse of the cellmate in the woods. That latter part causes Thorne to decide to stick to the plea agreement, in order to use the confession it elicited in charging their suspect with the murder of his cellmate. Legal wrangling ensues, with Thorne at his sneakiest. Sam wants no part of it, but Ronnie is willing to take the stand so his partner doesn't have to get involved. Cue another angry look from Sam, who gets called to the stand by the defense anyway. Will he torpedo the case or commit perjury?

As it turns out, neither of the above. He wriggles out of the crosshairs on a technicality, testifying that he didn't explicitly say the cellmate was murdered because he believed Thorne would figure it out. His willingness to bend allows Thorne to prosecute for murder. It's something important to note, as we saw Matt refuse to fall in line with Ronnie's review of the evidence in "Anonymous" and end up being discredited by Steel for it. Unlike Matt, Sam is willing to play along for the greater good, even if he absolutely loathes it.

Ronnie and Sam's partnership - and our relationship with the character of Sam - starts to find its legs in this episode. It's taking me a bit to warm up to Sam, because I'm still trying to feel him out. This is the second outing where we've seen he's got a temper; well, so did Matt Devlin, and Jamie Bamber delivered it with more fire and charisma. When their characters are displaying some of the same traits, it's impossible not to compare the actors. Paul Nicholls is, thus far, existing in the same place that Dominic Rowan does - he's capable enough, but there's an extra level that his predecessor had which he has yet to touch. For an actor just coming onto the show and getting comfortable with his fellows, though, he's doing well enough - and knowing which episode the sixth-series finale is based on and who's writing it, I have confidence that he'll have every opportunity to make his own distinct mark.

Speaking of Thorne, though, I have to finally give him props in this episode. I've said numerous times that I wished the character would find a personality - well, this week he thought outside the box and had some attitude to back it up besides. For the first time, I was actually interested in what he'd do next. It's been a long time coming, but I'm glad it did.

"Immune" is an interesting episode, because it gives some depth and spark to a pair of characters who benefit from it. I'm still not sure whether or not Law & Order: UK will ever quite be as good as it once was, but this episode certainly showed that it has the potential to be that good again, once the characters start finding themselves and their relationships again. Unfortunately, we may run out of time before it gets that far. Here's hoping that's not the case.

(c)2011 Brittany Frederick/Digital Airwaves. All rights reserved.