This episode scared the be-jesus out of me. Genuinely thrilling, with an interesting villain who develops through the episode from an innocent, if slightly odd, cable guy, to a stalker, and eventually a killer. Right from the opening sequence I was on edge, a stalker breaches the sanctuary of a young woman, and spies on her from her own attic. She runs to hide in her cupboard, her yapping dog barking at her side, only to be grabbed from behind out of the darkness by an unseen villain. Awesome.
We also get a glimpse of Nick Stokes life outside of work as a luna cable loving sports fan, and a dedicated crimestopper. This episode also introduces a selfless psychihc, who 'helps' the investigation, but ultimately puts himself in peril when trying to warn Nick.
Overall this was a very original episode, well acted and thrillingly directed. 10 on 10.