Malcolm puts Oliver and Thea in a dangerous situation that lands them on Lian Yu with Oliver's former enemy Deathstroke. In a flashback, Oliver and Maseo return to Starling City to retrieve the Omega bio weapon.

After hearing Ra's al Ghul's offer, Oliver returns to Starling City and contemplates whether he should accept it or not. Meanwhile, Quentin turns against the Arrow, and a new villain--Murmur--comes to the city to get revenge.

Oliver and Lyla team up on a secret mission for Diggle. Felicity finds out and disapproves of the plan and opts to stay behind. When Tobias Church launches a deadly assault against the city, Felicity must decide if she wants to send the recruits out sans the Green Arrow.