Police scientist Barry Allen travels to Starling City to investigate a seemingly impossible robbery from Queen Consolidated's Applied Science Division, and Felicity takes a liking to him... much to Oliver's dismay. Meanwhile, Sin asks Roy for help tracking down a missing friend, and Thea joins her boyfriend in the hunt, only for one of them to be injured.moreless
Infamous criminal Cyrus Vanch plans to take on The Hood to reestablish his reputation as Starling City's leading crime lord. Meanwhile, Oliver confronts his mother over the copy of the list that Walter found, and Quentin unintentionally endangers Laurel.moreless
While on vacation Oliver Queen's ship is destroyed in a storm and he is the only survivor. He finds himself trapped on an island for the next five years. Once he makes it back to Starling City he is reunited with his family and his former girlfriend, but they are unaware that he has changed... and has put the skills he learned to survive on the island to become the vigilante that the city needs.moreless
When convicted bomber Paxton Petty reappears to place bombs throughout San Francisco, the team take methods from the past and apply them to the present to find him.
When the M.A.N.T.I.S. uncovers an organization which runs underground, to-the-death blood sport matches, he helps a man who is forced to participate.