Oliver returns to the mayor's office and faces one of his most pressing issues yet - the forced release of dozens of unhappy criminals prosecuted by Adrian Chase. Meanwhile, a crate is delivered to Oliver's office containing a mysterious inactive person encased in concrete.
Season 5 Episode 21 of Arrow was watched by 1,650,000 viewers, resulting in a 0.60 rating in the 18-49 demographic.
After a unhappy shipwreck, billionaire playboy Oliver Queen was missing and presumed dead for five years before being discovered alive on a remote island in the Pacific. When he returns home to Starling City Oliver has been changed by his ordeal on the island. While he hides the truth about the man he's become, he desperately wants to make amends for the actions he took as the boy he was.
As the Green Arrow - a vigilante - he protects his city with the help of former soldier John Diggle, computer-science expert Felicity Smoak, his vigilante-trained sister Thea Queen, Deputy Mayor Quentin Lance, brilliant inventor Curtis Holt, and his new recruits, street-savvy Rene Ramirez and meta-human Dinah Drake.
Oliver has finally solidified and strengthened his crime-fighting team only to have it threatened when unexpected enemies from his past return to Star City, forcing Oliver to rethink his relationship with each member of his 'family'.