Supergirl, “Ace Reporter:” Every nanosecond brings danger as Lena Luthor’s ex comes to town with a medical procedure that may not be what it seems. Meanwhile, tension develops among the show’s second-string crimefighters.

The Flash, “The Once and Future Flash”: Barry travels to the future, to learn that Emma never returned from being Killer Frost, Savitar was defeated without the Flash learning his identity, and Mirror Master and Top continue to wreak havoc in Central City. Future Flash, taking a page out of the Arrow handbook, has become a mopey recluse in a bad wig. Can Barry get the old gang together and save the future? Can he save the doomed Iris? And will someone hand him a plot device in the last few minutes of the episode that he literally could have received at any other time in the episode?

Bonus: Killer Frost learns Savitar’s secret identity– but we don’t!

Arrow, “Dangerous Liaisons:” The Marquise de Merteuil and the Vicomte de Valmont use seduction to…. Wait, wrong Dangerous Liaisons. Everyone joins the chase after Adrian. Team Arrow may have to make an illicit deal with Helix, and hope there’s no double-cross, in order to stop the killer.