As Oliver (Stephen Amell) and Helena (guest star Jessica DeGouw) grow closer, Oliver trains her to be his ally, complete with showing her how to use a crossbow. Diggle (David Ramsey) disapproves of Oliver sharing his secret with Helena as he's not sure she can be trusted, but Oliver refuses to listen to his concerns. Helena's quest for revenge proves to be too strong for Oliver to handle after she kills the head of the Triad and all hell breaks loose.