The team goes after a burglar, and Oliver and Thea manage to corner him. He escapes when Thea loses consciousness and almost falls off a building. Malcolm reveals to Oliver that this is Thea's bloodlust; since she has not taken a life, the bloodlust is killing her. Felicity tracks the burglar again. Oliver stops him, but when it is revealed to be Roy Harper, Oliver's surprise allows Roy to escape. They track Roy to Palmer Tech, where they discover he is being controlled by a man who goes by the name the Calculator. Felicity tracks the Calculator through the web, who reveals he intends to shut down the entire city killing everyone in the process. The team locates his bomb and destroy it before it can shut down the city infrastructure. Meanwhile, Darhk's wife enters the mayoral race, Thea slips into a coma, the Calculator is revealed to be Felicity's father, and Nyssa escapes her cell in Nanda Parbat to offer Oliver a cure for Thea in exchange for Malcolm's life. In flashbacks, Reiter tortures Oliver for information on the maps he acquired, with Oliver starting to hallucinate seeing Shado.