In it, Superman -- who is apparently brainwashed by Rhea -- destroys the positron cannon before Alex can use it to destroy the Daxamite mothership and punches the Girl of Steel in the jaw and sends her flying right after the Daxamite queen finishes gloating.
Hopefully, in Monday's season finale we learn how Rhea got her hooks in the Man of Steel, but either way, the cousin-on-cousin fight will be physically and emotionally damaging for both of them. “Any time you find yourself squaring off against someone that’s family, it takes on a little bit more of a toll,” Hoechlin told Entertainment Weekly. “But that’s something you’re going to have to wait and see to find out; it’s a little more complicated than it appears.”
Supergirl (Melissa Benoist) challenges Rhea (guest star Teri Hatcher) to battle to save National City. Meanwhile, Superman (guest star Tyler Hoechlin) returns and Cat Grant (guest star Calista Flockhart) offers Supergirl some sage advice.
Glen Winter directed the episode with story by Andrew Kreisberg & Jessica Queller and teleplay by Robert Rovner & Caitlin Parrish.
Distributed worldwide by Warner Bros. International Television Distribution, SUPERGIRL is executive produced by Greg Berlanti (Arrow, The Flash), Ali Adler (The New Normal), Andrew Kreisberg (The Flash, Arrow) and Sarah Schechter (Blindspot, The Mysteries of Laura). Supergirl is based on the characters created by Jerry Siegel and Joe Shuster and appearing in DC Comics, by special arrangement with the Jerry Siegel Family.