Oliver and Felicity’s blissful getaway is cut short when Thea and Laurel pay them a visit and tell Oliver they need his help back in Star City. The city has been attacked by “Ghosts,” assassins led by a dangerous man named Damien Darhk. However, when Oliver returns, Diggle makes it very clear that he doesn’t want Oliver on the team.
When Brian helps Agents Harris and Boyle investigate the murder of a retired FBI agent, they’re shocked to find a link to the elusive head of a notorious drug cartel. Also, Brian reconnects with an old flame, Shauna but worries her renewed interest is really in the NZT version of him.
Fitz and the team enlist the aid of an Asgardian to unlock the secrets of the ancient monolith that swallowed Simmons, and Agent May is at a crossroads in her personal and professional life.
Picking up months after the Singularity attacked Central City, Barry is still struggling to forgive himself for Eddie’s death. Concerned about putting his friends in danger, Barry has pushed everyone away and has chosen to protect the city on his own. When a meta-human named Atom Smasher attacks the city, Iris tells Barry that he needs to let his friends help him protect the citizens of Central City. Meanwhile, Cisco helps Joe with his Meta Task Force.
When the body of a local college fraternity student is found gruesomely murdered, Castle has to go undercover as a professor in order to gain access to the victim’s world. However, he and Beckett soon discover that behind the fun and games of college are some darker secrets the university wants to keep hidden.
Almost two years after the Embassy attack in Islamabad, Carrie is building a new life in Berlin. But her peace is threatened when a request from her boss forces her towards the dangerous world she left behind.
As Alicia tries to revive her struggling law career, attorney Lucca Quinn becomes her competition; Peter engages Ruth Eastman, a new strategist for his campaign, changing the dynamic with Eli in the process.
Kiera pressures Carlos for more time; Kellog faces unexpected danger; the future soldiers plan a raid.
Erica Kravid reveals just how far she will go to protect the world from Evos. Tommy finds comfort in sharing his ability with Emily and a new-found popularity at school. Miko’s rescue mission comes up against some unexpected obstacles. Noah continues to work with Quentin in his search for the truth. Luke and Joanne continue on their deadly mission. Carlos’ search for answers causes him to dig deep to find the hero within.
Phil and Claire are hurt when Alex lies about her college move-in date and Luke doesn’t want to spend the day at Phil’s open house; being landlords stresses out Mitch and Cam.