Oliver and the team struggle to come to terms with Laurel’s death, especially Diggle who is overwhelmed with guilt for choosing to believe Andy had changed. Meanwhile, Lance refuses to believe his daughter is really gone and asks Nyssa to help bring her back. A recent Black Canary sighting in Star City only seems to prove his theory that Laurel isn’t actually dead.
Courtney invites everyone to a frat party at SUC, but when they wake up the morning after, Imogen is missing and the Foursome must retrace their steps to find her.
Preparations for winter continue, and focus centers on finding food. Heimo pursues caribou meat, while Tyler & Ashley score big game, building their confidence in the bush. Bob & his daughter reminisce on the past as they arrive at their cabin home.
To celebrate Robin's birthday, the gang put on a talent show, but the festivities are interrupted when Adam and Kerry clash over his flirtation with Fay. Plus, some experimentation with Fay's drug stash sees everybody's deepest desires emerge.
As the holiday from hell draws to a close, Adam falls off the wagon and Robin's party descends into substance abuse, blazing rows and awkward sexual encounters.
A meta-human with super strength named Griffin Grey mistakes Harry for Earth-1 Harrison Wells and kidnaps him, demanding that Wells cure him from his current condition. Realizing another brilliant Wells could help track Griffin’s location, Barry asks Jesse to help. Meanwhile, Wally corners Joe about The Flash.
Firehouse 51 unites to help a young boy in tragic circumstances. A high-powered political consultant helps Casey navigate a potential scandal. Cruz makes a mistake that nearly costs him his life.
Evan is excited to open his first bank account, but is unsure if he should use his American name or his Chinese name on the account. As a result, Louis and Jessica reveal how they acquired their American names and recall the first time they met.
Refusing to accept that their crazy days are behind them, Jess and Cece abandon their low-key bachelorette party plans and seek a night out to top all others.
Following a stunning betrayal to their team, Brian and the FBI race to stop an NZT-enabled Sands and his associates from orchestrating an international incident. Also, Brian experiences devastating side effects when his NZT immunity starts to wear off.
When Jimmy has trouble admitting that he's 51, he throws himself a second 50th birthday party. The party triggers flashbacks of where he was a year ago, showing Jimmy what a difference his family has made in his life.
Yolanda takes her friends to task for questioning her health issues; wounds are reopened when Kyle's sister, Kim Richards, returns to talk about her difficult year; Eileen confronts Lisa Vanderpump, causing her to break down in tears.
Jake Anderson tries a dangerous short cut with only one working engine on the boat. Casey and Josh perform surgery at sea. Edgar Hansen captains the ship while his son Eric works as greenhorn. Captain Keith turns his life around.
The murder investigation of a suburban mom takes a turn when her child is abducted.
A teen patient with abdominal pain firmly refuses any drugs. Meanwhile, Dr. Halstead reconnects with his past when treating a patient; a pregnant woman does everything in her power not to deliver the child; and Dr. Rhodes tries to avoid family issues.
Lex finds out that a woman who had close contact with an infected patient has disappeared.
Harry loses his cool with 3 swimmers that he's forced to rescue just seconds after warning them not to swim in a dangerous area. However, calling them "imbeciles" and "idiots" puts him in hot water.
A possible sighting of Genghis Khan's lost tomb dead patches in the desert and the world's oldest and strangest lakes.