13. Star City Slayer

Complete story — includes the ending

Members of Team Arrow receive threatening notes and discover a similar note at the murder scene of a councilman who previously worked with Ricardo Diaz. Tracking a drug used to immobilize the victim, they discover the hiding place of the "Star City Slayer," who is revealed as Stanley. He slits Dinah's throat, but Curtis cauterizes the wound, saving her life. Stanley confronts Oliver, Felicity, and William at their apartment, claiming to be the only one who truly understands Oliver. While Felicity distracts Stanley, Oliver subdues him and he is sent back to Slabside. William, wanting a normal life, chooses to live with his grandparents. Curtis accepts a job in Washington, D.C. and leaves Star City, signing sole ownership of their Helix company over to Felicity. Meanwhile, a medical checkup discovers something important about Felicity. In flashforwards, Dinah, Roy, William, and Zoe find the Arrow bunker and get into a fight with Blackstar and Connor Hawke. Blackstar claims that Felicity is alive before revealing that she is Mia Smoak, the daughter of Oliver and Felicity, and William's half-sister.