I happened on Heroes this evening.

As the storyline involves time travel and attempts to intervene in the course of events, it would seem to qualify as SF TV.

It seems to have been around for at least one previous season, but I was not previously aware of it.  Anybody out there who can comment on the back story?

ADDENDUM:  After posting the above, it occurred to me to do a search on "Heroes", which produced a half-dozen hits. While I've not had time to digest them all, they appear to be brief squibs and notices of cast members coming and going....rather than discussions of the story.

Best regards,  4merCL