Cadmus just won’t stay away. After they grabbed Mon-El, they use him as bait to lure in Supergirl. Meanwhile, The Guardian has some competition with a new vigilante in town. Unfortunately, the newcomer is playing judge, jury, and executioner and is willing to let everyone believe that The Guardian is responsible for the recent murders. At the DEO, J’onn is still recovering, and Alex confronts Maggie.
James Olsen is having a tough time protecting National City as The Guardian when a new vigilante shows up and makes it look like he’s a murderer. Winn wants to lay low, but James wants to clear The Guardian’s name and catch this vigilante. When they come face to face, the vigilante says that he’s keeping the city safe just like The Guardian. He thought they could be allies, but The Guardian won’t do what is necessary. James won’t kill anyone since he knows that isn’t the way, but the vigilante doesn’t care. It turns out that the vigilante has a system as to his victims. He’s going after those that he feels have gamed the system and got off on a technicality.
Kara and Alex aren’t so sure about The Guardian. Kara doesn’t like that he hides his identity from her, and she’s not so sure if National City should be putting their trust in him so fast. Every time that The Guardian is mentioned, Winn acts weird. He’s terrible at hiding anything, and Alex sees right through it. She realizes that he knows who The Guardian is. She asks him point blank, and it takes about ten seconds before Winn cracks and reveals The Guardian as James Olsen. They keep it hidden from Kara, for now.
Meanwhile, Mon-El is locked up at Cadmus, and Lillian Luthor is prepared to use him to get the real prize, Supergirl. By threatening his life, Lillian gets Supergirl to come straight to her. Supergirl ends up face to face with J’onn, except it’s not J’onn at all. It’s the real Hank Henshaw. Cadmus saved him and gave him powers. He’s now Cyborg Superman, and he wants to end alien life on this planet. Cadmus’s agenda is kind of an oxymoron. They want to end alien life, yet they are using alien technology to create super soldiers. Do the ends really justify the means to them?
For Lillian, it’s all about her family. She really has a hatred for aliens because Superman exposed her son, Lex, as being evil. She thinks that their kind will continue to poison the Earth. Lillian asked for Kara to use up her powers, so she can become human for awhile. Kara agrees in order to save Mon-El, and then Cadmus takes a lot of blood from her. Kara and Mon-El look to be locked up for awhile, until a mysterious man comes to help them get out. Jeremiah Danvers is alive and well and helps them escape Cadmus. Kara tries to convince him to come with them, but he stays behind to hold back Cadmus. When Kara, Alex, and the DEO go back to the site, Cadmus is long gone.
J’onn is having a tough time still recovering from the parasite. M’gann’s blood transfusion saved his life but at a very costly measure. J’onn is seeing things that aren’t really there, like his family or a White Martian about to attack. When J’onn looks at his blood, he sees something disturbing. He knows the truth; M’gann is a White Martian. She tries to explain that she’s not like the others. She tried to save the Green Martians, but she couldn’t. M’gann explains that the White Martians experimented on their own, and her blood is actually turning him into a White Martian. That can’t be good. J’onn can’t let go of his anger toward the entire White Martian race, so he locks M’gann up at the DEO.
Alex has been having a tough time after coming out and learning that her crush, Maggie, doesn’t have the same feelings. Maggie wants everything to go back to normal, but Alex can’t do that. Alex finally speaks up and lets Maggie know how she feels. She tries to explain to Maggie the pain that she put her through. Alex is too crushed to just be friends right now. She doesn’t feel liberated; she only feels pain. Some time later, Maggie goes to see Alex. She explains that she cares for Alex, and Alex is important to her. She hopes that they can be friends because she can’t imagine her life without Alex in it. Alex is still hurt, but she’s willing to try and be friends.
