Complete story — includes the ending
The team goes after a burglar and Oliver and Thea manage to corner him. He escapes when Thea loses consciousness. Malcolm reveals to Oliver that since she has not taken a life, the bloodlust is killing her. Oliver finds out that the burglar is Roy Harper. They free Roy from the control of a man who goes by the name 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 manages to stop the plan. Meanwhile, Ruvé enters the mayoral race. Thea slips into a coma. The Calculator is revealed to be Felicity's father, Noah Kuttler. Roy decides to leave again. Nyssa escapes her cell in Nanda Parbat, visits Tatsu Yamashiro and convinces her to give her the Lotus, a cure for Thea's bloodlust. She demands Oliver to kill Malcolm in exchange for Lotus. In flashbacks, Reiter tortures Oliver for information on the maps he acquired. Oliver has a mystical meeting with the soul of Shado, who gives him a special stone. He reveals to Taiana that he killed her brother.
Sources and content license
Source and revision history · Adapted from Wikipedia contributors, Arrow season 4. HTML formatting and reference markers removed. · Content license