Last night, Luther premiered its penultimate episode, and, boy, was it a heart pounder. After having nabbed the creepy, toothbrush-sucking serial killer Paul Ellis, Luther must now catch a sawed-off shotgun-wielding, vigilante serial killer (Elliott Cowan) who is using social media to drum up support for his cause. Now, Luther is in a race against the clock to stop him before he kills again. Things don’t start off so white-knuckled, though, as John is settling in to his relationship with Mary, a side of John we’ve rarely seen in the series. The moment where Ripley shows up at his door and John invites him in is one of the most endearing of the entire series in my opinion. It shows how far the two have come as partners over the years. It isn’t long before that moment is gone and things return to the roller-coaster ride of emotion we’re used to in Luther.

Writer/creator Neil Cross reminds viewers that this is a series that isn’t afraid to take it to the limit. Episode three features terrific performances from Cowan as the desperate vigilante who wants justice for his wife, and Warren Brown as DS Ripley who proved his loyalty to Luther last episode. You couldn’t pry me from my screen with a crowbar during Brown and Cowan’s scenes together. The tension was palpable. Cross has put his foot on the accelerator, and it doesn’t look like he’s going to ease up going into the final episode.

In my opinion, Luther is one episode away from cementing itself as one of the best police procedurals ever on television. Certain elements of the procedural portion of the show may be a bit predictable, but Cross has created characters that are a hundred times more compelling compared to others. What makes Luther so great is its ability to draw you into this world and leave you wanting more each and every time. This episode is no different and, in fact, leaves you picking your jaw up off the floor, wondering how things will end for Luther.

The final episode airs tonight on BBC America. Tune in!