'Supergirl': "For Good" Preview Released

The CW has released a promo for "For Good," the upcoming twelfth episode of Supergirl's third season.

The promo reveals a National City in chaos with Reign (Odette Annable) still on the loose and the threat of even more Worldkillers looming large. It also reveals the return of Morgan Edge (Adrian Pasdar) and hints at real trouble for Lena Luthor (Katie McGrath). Lena can be seen foaming at the mouth, literally, while a decidedly not in costume Kara Danvers/Supergirl (Melissa Benoist) flies her friend away from danger.

According to the official synopsis of the episode, Edge's return, Lena's situation, and the fear of Reign may all be connected. Someone attacks Edge and, while he survives, he points the finger at Lena and vows to destroy her. And when it comes to Reign, her not-so-Worldkiller alter ego, Sam, has realized that something is going on with her, prompting Alex (Chyler Leigh) to run some tests to find out what is going on. Those tests may just be another step towards Supergirl figuring out who Reign is. As we saw in tonight's episode, Supergirl is aware that there is a human side to her ultimate nemesis and, according to Benoist, it's only a matter of time before the Girl of Steel finds out that Reign is both her enemy and her friend.

"It does seem like it's only a matter of time," Benoist said. "What I think is the most important is how Sam is going to react, because obviously she has no awareness of what's happening right now. The entire arc of the season is this identity crisis for every character, so if Kara finds out about Sam, if and when, it's definitely going to be part of that journey."

That journey may involve humanizing and redeeming Reign, though Benoist admitted that won't be easy.

"That would be difficult," she said. "But knowing Supergirl, and how she tends to deal with situations, and how she thinks everyone deserves a second chance, and that you can change and be a better person and a hero, I think she'll try to help her."

Supergirl airs Mondays at 8/7c on The CW. "For Good" premieres January 29.