Oliver and Felicity's getaway is cut short when evil villain Damien Darhk threatens the city.
Team Arrow act fast when they uncover a HIVE plot to destroy them once and for all. Thea helps Oliver as he struggles with his conscience.
The victims of a highly intelligent serial killer are piling up. A professor who teaches forensic psychology is brought into the fold and forces the team to consider the notion of sending civilians to the other side.