Inmate 4587. That's Oliver queen's newest identity at Slabside Maximum Security Prison, where he's been keeping his head down and avoiding conflict since he publicly revealed his alter ego as the Green Arrow five months ago. With Team Green Arrow protecting Star City while Oliver's behind bars, there have been no vigilante sightings... until a mysterious new Green Arrow appears. Meanwhile, John Diggle and Dinah Drake are leaving their costumes behind, .hut not everyone is following suit. Oliver's limits will be tested when he and the crew are pitted against the most ruthless villains they've ever faced, forcing him to seek redemption for his redemption for his family, his team and his identity while he questions what it truly means to be a hero.