Oliver brings Sara into the Arrow team. Watching Oliver and Diggle spar with Sara and talk old scars, Felicity starts to feel left out. The team is investigating a villain named William Tockman, a.k.a. The Clock King, who is a brilliant thief armed with technology that can open any bank vault in Starling City. After The Clock King infiltrates the computer systems in the lair, Felicity feels pressure to prove her worth. When she gets a lead on Tockman's whereabouts, she heads out without the team, putting her in peril. Meanwhile, Oliver throws Sara a welcome home party, but Laurel refuses to attend. After Lance makes his case for a family dinner, Laurel acquiesces, but when Oliver shows up with Sara, she loses her temper on both of them.

Following Slade's return and his promise to make good on his threat to destroy Oliver's loved ones, Oliver focuses all his energy on preparing for battle with his former friend. Sarah tries to help but, fearing for her safety, Oliver pushes her away. Meanwhile, Diggle is recruited by Amanda Waller and A.R.G.U.S. to stop a warlord he knew from his time in Afghanistan. Always the solider, Diggle agrees to help. However, he's not prepared when Amanda introduces him to the rest of the team - Deadshot, Bronze Tiger and Shrapnel, all criminals he and Arrow helped put away. Lyla defends the team and explains the world is a complicated place, but Diggle isn't sure he agrees. When the mission takes a dangerous turn, Diggle is forced to make a difficult decision.