* THE KILLING. Netflix.
No, it really can't be killed. The twice-canceled series starring Mireille Enos and Joel Kinnaman as Seattle homicide detectives - now linked by a terrible secret - has been brought back by Netflix for six (supposedly) final episodes, all of which were released for streaming Friday. I didn't want to get drawn back in, but the four I've seen are intriguing enough to make me want to see if Season 4 can, at last, stick the landing. And at least on Netflix, I won't have to wait weeks to know.
* THE STRAIN. 10 p.m. Sunday, FX.
A clandestine autopsy shows CDC researchers a little more of what they're up against in Guillermo del Toro's horror series, while one member of the team has a confession.
* HELL ON WHEELS. 9 p.m. Saturday, AMC.
All aboard? Season 4 of the series about the building of the first transcontinental railroad gets underway.
* THE LEFTOVERS. 10 p.m. Sunday, HBO.