Complete story — includes the ending
In flashbacks, Maseo and Oliver go after Shrieve to see if he has a cure. They only succeed in leading Shrieve to their location, with Akio dying in Tatsu's arms. In the present, Diggle and Laurel patrol Starling City, taking on any criminals they meet. Thea finds Roy and reunites with him. Oliver learns that Maseo is the one who provided Ra's with the Omega virus when he originally came to Nanda Parbat. Sneaking away from the castle, Oliver is shown to have been in league with Malcolm, that his agreement to become Ra's' heir was a charade to get close to Ra's and slowly dismantle the League from within. On Oliver's advice, Malcolm uses Tatsu to convince the team of the truth. The group, including Tatsu, Ray, and Malcolm go to Nanda Parbat, where Tatsu kills Maseo just before they are overrun by the League and captured. Malcolm reveals Oliver's treachery to Ra's, but Oliver manages to convince him of his loyalty. Roy secretly leaves Thea. Ra's exposes the team, excluding Tatsu, to the virus before sealing them away in a cell. Afterward, Oliver and Nyssa get married.
Sources and content license
Source and revision history · Adapted from Wikipedia contributors, Arrow season 3. HTML formatting and reference markers removed. · Content license