Caitlin takes Barry out to a local karaoke bar to help them both find new loves. Caitlin strikes out but Barry meets a sports reporter and asks her out for a date. Cisco considers Hartley’s dangerous offer. The team searches for Shawna, a meta-human with teleportation powers.
Castle takes on a routine P.I. case, but the investigation turns deadly when he witnesses a murder.
When the Gage presentation falls apart, Marty comes up with a last-ditch plan that includes orchestrating a move that a volatile Ellis doesn’t want. Jeannie has a less-than-encouraging meeting with a headhunter regarding her prospects in the job market. Doug petitions to join Clyde and Kelsey’s new business venture.
Louis is gaining leverage in his quest to become a name partner of the firm and the Pearson Specter team is dealing with the fallout of Louis learning Mike’s secret.
Lives are at risk as Clarke and Lexa encounter a new enemy. Bellamy and Lincoln agree to work together to break into Mount Weather. Murphy helps Jaha confront his past. Meanwhile, Indra makes Octavia an offer she can’t refuse.
Arsenal and Diggle confront Laurel about trying to step into her sister’s shoes and warn her to stop before she gets herself killed. However, when Brick kidnaps the city’s Aldermen and threatens to kill them all unless the police evacuate The Glades, it’s all suits on deck. Meanwhile, Ray steps in to help Lance and the police force fight Brick, showing Felicity a new side of her boss. Malcom tells Thea that Ra’s al Ghul is after him and his family and they must leave town immediately.
When Abbott’s old boss, Agent Peterson, threatens Abbott’s career – and possibly his freedom – Jane devises a risky plan to protect his friend’s future.
Peggy may be in more trouble than usual when fugitive Howard Stark suddenly returns for mysterious reasons. And Chief Dooley chases a new clue all the way to Europe that threatens to destroy Peggy’s future at the SSR.
Dr. Wells’ former protégée, Hartley Rathaway, returns to seek revenge on his mentor after being affected by the particle accelerator explosion. Now able to manipulate sound waves, the brilliant Rathaway is a dangerous threat to both Wells and The Flash. Meanwhile, Iris is thrilled when she’s hired by the Central City Picture News as their newest cub reporter. Unfortunately, her editor pairs her with a veteran reporter, Mason Bridge, who wants nothing to do with her. Cisco recalls his first day on the job at S.T.A.R. Labs when he met Hartley and Caitlin. Joe asks Eddie for a favor but asks him to keep it a secret from Barry.
Marty and Jeannie pitch opposing strategies to a Seattle-based skin care company. Doug, fed up with Sarah’s antics, passive-aggressively puts his foot down. Clyde begins discussing a business idea with an unlikely partner.