I thought the episode where....dang it, I always forget his name....Magnus or whatever....the pretty boy guy. Anyway, the one where he gets stuck between 1996 and 2004 where his girlfriend Penny has to serve as a "constant" for him. I usually like time travel stuff, and I thought this episode was pretty well done.
I'm glad the black smoke plays a big role at some point, cause that's the only part of the show I thought was really goofy thus far.
I just realized that S4 only has like 14 episodes, so this won't take me too long....then it's on to S5!