On Quantico Season 3 Episode 9, Syrians under CIA's protection are murdered, all except one. It turns out they were there to speak at the UN about war crimes they witnessed happening while in Syria. Shelby's also set to testify.
While at dinner with Alex, someone takes a shot at Shelby, killing an innocent instead of her. The one Syrian who escaped the massacre at the CIA safe house is named Nasir, and he reaches out the Shelby.
Despite concerns from Ryan, Shelby insists that their team protect Nasir, not the CIA. While bringing him in to safety, three IRA members try to take Shelby and Nasir out.
Jocelyn mentions that Frank was undercover with the IRA four years ago, and his cover is still intact. It takes some convincing, but Owen agrees to give Frank a shot.
Frank tells Connor information on the security protection detail for Shelby and Nasir. It's a trap. Alex and company are there waiting for Phalen and other goons to show up to kill them. It works.
However, Nasir is fatally wounded. Shelby testifies at the UN to honor his legacy.
When Alex and Owen arrest Connor, he swears he'll kill everyone they love as retaliation.