The teams are dropped on the banks of the Tazlina River and tasked with building log rafts. Faced with punishing rocks and class four whitewater, their designs are crucial to their success and survival.
In the aftermath of Olivers fight with Ras al Ghul, Diggle and Arsenal continue to protect the city in the Arrows absence. However, after three days without hearing from Oliver, they begin to fear the worst may have happened to their friend. Felicity refuses to believe that Oliver could be dead until Merlyn pays the team a surprise visit. Thea suspects there is something more behind Olivers disappearance and asks Merlyn for a favor. Meanwhile, Ray tests a part of his new suit and Laurel takes up the mantle of the Black Canary.
While Kitty tries to find a runaway teen, Sherlock and Joan work a case in which the murder of a brilliant bioengineer looks to be at the hands of a drug cartel. Also, Joan makes a major life decision but worries it will impact Sherlock negatively, not knowing that Sherlock has big news of his own.
When Luke finally returns home after wrapping up his Moon or Shine Tour just days before he and Rayna tie the knot, Rayna starts to feel conflicted about leaving their kids to go out on the road again, especially after she discovers that Luke has been making parenting decisions without her. Meanwhile, Will invites Layla on tour in an effort to keep her close but when he sees her flirting with his boss at a party, he begins to feel like he’s losing control of their situation. Then, Teddy uses his Mayoral powers to track down a recent flame and Sadie crosses paths with an unexpected ex. Later, after getting some advice from his mom, Avery makes an unexpected decision.
A house fire sees the team attempting to save the lives of a couple trapped inside. Chief Boden prepares to start his new family. The combination of life at work and home sees Casey and Dawson drifting apart.