There's a new crimefighter, Vigilante, in Star City... and his take-no-prisoners approach forces Oliver to confront his past when he killed criminals. Meanwhile, Thea helps Quentin out, and Prometheus makes contact with his secret ally.

After Prometheus attacks and nearly kills Curtis, the team discovers that he is connected to one of the businessman Oliver killed when he first returned to Star City. Now Prometheus sets out to prove that everyone close to Oliver dies... by killing someone he knows. Meanwhile, an old friend returns to the bunker.