'Arrow' season 5 midseason finale spoilers, news: Oliver's past connection with Prometheus to be revealed; Flashpoint story arc continues

The CW's four-way superhero crossover event wrapped up last week, but it seems that more Flashpoint changes will continue to be explored in the upcoming episodes of "Arrow."

In the show's last episode, Team Arrow took on a huge extraterrestrial threat with the help of The Flash, aka Barry (guest star Grant Gustin), and Supergirl (guest star Melissa Benoist). "Invasion!" saw Oliver (Stephen Arnell) deposited in a reality wherein his loved ones never died. The crossover's last leg revealed that the Dominators were actually after Barry, but they ended up leaving Earth thanks to the heroes.

Speaking with The Hollywood Reporter, co-showrunner Marc Guggenheim talked about how the Flashpoint story arc will continue on in the episode airing next week. "The midseason finale, there's a fair amount of discussion about Flashpoint, given the fact that the crossover outed Flashpoint to the Arrow characters who weren't Felicity," Guggenheim said. "They deal with -- I think in some humorous ways, actually -- some of the ramifications. For example, I think Curtis is concerned that maybe he was straight originally, as one example," he added.

Titled "What We Leave Behind," next week's episode certainly feature something special for fans. According to Guggenheim, some of his ideas that didn't make it to the 100th episode will be in next week's "Arrow" as it features a clue connecting Prometheus to Oliver's past. Moreover, viewers will see Oliver with a new sense of purpose as he reaffirms his bond with Thea (Willa Holland).

"There was a lot of temptation to do the crossover at a different time or, like you [suggested], 'cheat the math,'" he told TV Line, "but I actually took an idea that I had for the 100th episode and moved it to the 101st, and that is flashbacks to Season 1"

The fifth season of "Arrow" airs every Wednesday night at 8 p.m. ET on The CW.