Supergirl: “Survivors”
The Maid of Might uncovers an alien Fight Club, and we learn something about Miss Martian that won’t be too surprising to comic-book fans, but which may mean something different in the DC TV-verse.

The Flash: “Monster”
Cisco has suspicions about the new Harrison, as the Flash meddles with a mystery that wouldn’t be out of place on Scooby-doo (though the monster itself has a sort of “Alien meets Cloverfield” design). Caitlin gives her mother’s advice the cold shoulder.

Arrow: “Targets”
Church, shockingly, learns the Arrow’s identity, and Ollie must take desperate actions.

Legends of Tomorrow: “Abominations”
The Legends battle zombies during the Civil War. Does anyone else feel like the episodes this year have premises generated by a game of Mad Libs?