Black Siren returns to give Chase help; Felicity plans a birthday party for Oliver; Lance is angry with Rene for missing the custody hearing about his daughter.

Oliver assembles a group of unlikely allies – Slade, Nyssa, Merlyn and Digger Harkness – to engage in an epic battle against Chase and his army.

Oliver faces the forced release of criminals prosecuted by Adrian Chase, while a crate is delivered to Oliver’s office containing a corpse in concrete.

Prometheus goes to extreme lengths to destroy Oliver. In flashbacks, Oliver’s violent tendencies come to a head in a confrontation with Anatoly.