@LiberalLibrarian I'm going to say Alphas. Sy-Fy killed it suddenly as part of their rebranding into a crap network. The season 2 (and series) finale was one of the darkest, unresolved cliffhangers I've ever seen.
@LiberalLibrarian (and I know you said 1 season but I couldn't think of any bedsides Firefly, which is obvious). Check out Killjoys though. It could totally be set in the same setting as Firefly.
@ianthealy I haven't watched anything on Sci-Fi since BSG.