Batman and Oracle are having an argument. Batman thinks Batgirl failed in her last mission because the man died. Oracle disagrees. Just then Cassie comes in and she and Batman head out on a rescue mission for a little girl who has been abducted.
Before they get there Batman explains to Cassie that their job means they must do the impossible. Cassie claims to have no idea what he is talking about. They then attack the hideout and everything goes according to plan until a meta-human comes in. Batman is concerned since Cassie has never seen or fought a meta before. Batman gets the girl and manages to get her to Cassie and tells her to flee.
Once outside Cassie hides in a van with the girl. She has a flashback of life with her father when the little girl starts crying and wants to be returned to her own family. The meta-human attacks and breaks in with Batman's insignia in hand. Cassie then flashes back to Batman's lecture about doing the impossible. With that she attacks the meta-human's throat. With every swing she hits him in the same spot. The barrage leaves him dazed, and she manages to take him down before collapsing herself. Batman picks her and and is very proud of her performance and tells her "Good Job"
He takes Cassie back to the Clocktower before going home and speaking with Alfred. He then gets a message. It is a video that reveals Cassie as a little girl, brutally killing a man. He is horrified.