This year's "Arrow/ The Flash" crossover introduced a lot of new storylines for both shows as well as the upcoming spinoff, "Legends of Tomorrow." The episodes introduced Hawkman (Falk Hentschel) and Hawkgirl (Ciara Renee), and Arrow (Stephen Amell) and the Flash (Grant Gustin) were seen teaming up to prevent Vandal Savage (Casper Crump) from killing the two heroes.

 In the first episode, the pair faced off against Vandal but failed to defeat him, and Oliver learned that he might have a son with his ex-girlfriend Samantha. After Felicity (Emily Bett Rickards) learned about it, the two had a fight as she accused him of keeping his son a secret from her. In the second episode, Barry ran fast enough to travel through time and warn Oliver about their mistakes, and this time they were able to defeat Savage, and all was well between Oliver and Felicity once more.

But though Barry and Oliver were able to change the outcome of their battle with Savage and Oliver was able to save his relationship with Felicity, the executive producers of The CW shows said that there will be serious repercussions that will result from the heroes' actions which will affect the people close to them.

Speaking with Variety, "Arrow" executive producer Wendy Mericle said that though Oliver was able to hide his son's existence from Felicity again, it's only a matter of time before she learns the truth.

"It's definitely going to come to a head in the middle of the season," Mericle said. "The fact that he's keeping this from her…true to what we've done on the show, if there's a secret somewhere, it's going to come out and it's going to have serious consequences."

The executive producer added that the truth will test the couple's relationship and that there will be "some fallout for both of them" when Felicity finds out about Oliver's son.

As for what awaits Barry after he changed things in the past, executive producer Andrew Kreisberg said that there's "always a price to be paid" and that it will definitely come back to haunt those who change the timeline. Executive producer Marc Guggenheim said that the reason why time travel should not be used to change the future will be revealed in "Legends of Tomorrow" and that they are going to explain that "very definitively."

"The Flash" airs Tuesdays at 8 p.m. and "Arrow" airs Wednesdays at 8 p.m. on The CW.