“Damage” is episode five of season three of Supergirl.
The driver of a prison bus is being held at knifepoint when Supergirl stops it and Alex drops in the back. Afterwards, Supergirl asks Alex if she’s holding up okay.
Sam is dropping Ruby off at school; Ruby mentions what happened in the previous episode, “The Faithful”, when Sam saw her skin covered in writing and a strange person. Sam insists it was just a dream. Even though she was awake. After Ruby gets out, she’s talking to a boy when he collapses, spasming.
James is talking to Lena when Kara joins them both in the office. Then sees Morgan Edge on the television and says to turn it up. Edge is at the Luthor Children’s Hospital, where one of a number of children in different hospitals has been admitted with lead poisoning. Which Edge says was caused by the lead bomb Lena built to drive off the Daxamites in “Nevertheless, She Persisted”.
Alex and Maggie are talking. Because Alex really wants children and Maggie really does not, they are splitting up.
Lena and Kara find Sam at the hospital; Ruby’s friend is one of those affected. Lena sees Edge and confronts him; Kara says that Supergirl pushed the button so is just as much to blame. Edge tells them the tech was all Luthor. Lena poisoned the children.
Kara, Sam and Lena arrive back at CatCo. Lena wants every bit of data Edge has seen. Sam and Kara reassure her, but Lena is concerned it might be true. James joins them. Lena thinks he’s going to have a go. He isn’t, but he does think Lena should step down from CatCo, so that whatever they report, good or bad, comes off as the truth. Lena agrees and delegates James to run CatCo until this is resolved. And she’s going to step down from L Corp. She doesn’t want to be accused of covering things up or profiting from the sick. A parent arrives in the office and says Lena needs to answer for what she’s done to his son. Lena is going to hold a press conference.
There’s a demonstration at the conference as Lena is explaining she doesn’t know if her device hurt the children and is stepping down for the moment. Kara hears something in the crowd, but doesn’t see the woman with the gun until she opens fire. James gets hit knocking Lena out of the way.
After the bullet is removed, James tells Winn and Kara he understands why the woman, a parent, did it. Not saying Lena is responsible, but the device was jury-rigged. Winn is testing the device to see if it gives the same results as before. It doesn’t. There’s a much higher chance it could be a problem than originally thought.
Lena is staying over at Sam’s, feeling guilty. Sam reassures her. Kara arrives later to find Lena drinking alone. Lena knows Kara is hiding something as she says Kara is terrible at hiding things from her. Lena believes she is responsible.
Sam and Kara, at the very least, are not so convinced, and go digging into things to be certain.