At the end of The Flash's second season, Barry Allen traveled back in time and saved his mother from being mudered by the Reverse-Flash.
The ripple effect this had on history created an alternate timelines, nicknamed "Flashpoint," which radiated out from that moment and has impacted reality going into the show's third season.
The catalyst for this decision was the murder of Henry Allen, Barry's father, which came literally just hours after Barry finally believed he had come to terms with the death of his mother. When Henry -- played by TV's first Flash, John Wesley Shipp -- died, Barry got down to business, got Zoom taken care of...and then almost immediately went back in time.
When season three starts, Barry is still living happily with both his father and mother, neither of whom met their end at the vibrating hands of super-speedsters. Things seem ideal, until Barry realizes that the world he created is making his own history unravel.
Today, ComicBook.com spoke with Shipp, who told us that not only did he think Henry would approve of his son's decision, but he knows for a fact that Barry's father would be upset, because they've already had this conversation, back in season one.
"Henry would be very, very concerned," Shipp said. "We already know, becuase he said to him from the jail cell when Barry said 'I could undo all of this, I could go back and save mom,' Henry told him, 'No. You can't. There are unintended consequences to things. Things happen, maybe not for a reason, but things happen the way they do and when you go back and you fool with something, you may be thinking you're creating an idyllic present and future that you want, but it's like a Pandora's box: you have no idea what you're opening. So Henry would be dead set against it; we already know that."
Will Barry end up having that conversation with Henry again, now that he's already made the mistake? Shipp remained mum, although he did have plenty to say about Barry's relationship with Jay Garrick, The Flash of Earth-3, whom Shipp also plays.
Shipp teased that Jay is not entirely confident of Barry's motives or competence, given that he's already altered history to suit himself once, and that their relationship will be "emotionally cooler" than the warm one he previously had with series star Grant Gustin.
Supergirl airs on Mondays at 8 p.m.; The Flash on Tuesdays at the same time, Arrow on Wednesdays, and DC's Legends of Tomorrow on Thursdays. The Flash will debut its new episodes on The CW starting October 4; Arrow, October 5; Supergirl, October 10; and DC's Legends of Tomorrow October 13.