I understood that it was a flashback and that most of part 2 takes place before part 1, as we get filled in on the backstory to the main drama.
I'm glad that it wasn't Clark who turned evil, and it makes sense that it was Luthor's cloned Superman who went rogue. I'm looking forward to part 3 to see if Clark is really dead (and if Lois has figured out that he was the original Superman) and if we can get some semblance of a happy ending out of this interesting, albeit tragic, scenario.
Kathy
