Sam has a vision of Dean shooting a defenseless man, and they go to the town of River Grove, where they find the townspeople have been possessed by a virus…

Felicity’s past as a crusading hacker is revealed when someone uses a super virus that she designed to bring Starling City to a standstill. Meanwhile, Oliver and Thea work on…

Oliver teams up with a surprising force in an attempt to stop Damien Darhk and his magic once and for all.