An alien presence arrives on Earth with the intention to end all suffering and guide humanity into a utopia. But when the aliens refuse to reveal their appearance, some wonder if this dream is instead a nightmare.

A well respected surgeon is accused of plotting to commit a crime; Ruth suggests that Courtney Paige hire Jason for business in another state, hoping to remove him from Alicia’s life.

Carrie follows a lead.

Gloria’s plans for a White Christmas don’t go as planned.

Oliver makes a bold move against HIVE when the city is attacked. Meanwhile, Malcolm checks in on Thea and leaves her with a warning; and things take a horrible turn when Damien Darhk retaliates in a brutal manner at Oliver’s mayoral holiday party.

S.H.I.E.L.D. and Hydra go head-to-head in a battle that will change Coulson’s world forever. While Daisy and her team of Inhumans fight to keep Hydra at bay, Coulson and Fitz take the ultimate risk.

When Mark Mardon AKA The Weather Wizard returns to break Leonard Snart AKA Captain Cold and James Jesse AKA The Trickster out of Iron Heights, Barry must stop these rogues from taking over Central City during Christmas. Meanwhile, Joe and Iris meet Wally West.

A new threat emerges.

Gloria wins a silent auction to have a therapist come for an afternoon with the adults; Haley and Alex consider dumping their boyfriends.

Oliver and Barry Allen take Kendra Saunders and Carter Hall to a remote location to keep them hidden from Vandal Savage while they figure out how to defeat him. Malcolm arranges a meeting between Vandal, Green Arrow and The Flash that doesn’t go as planned. Meanwhile, Felicity, Thea, Diggle and Laurel work with Team Flash to come up with a weapon powerful enough to destroy Vandal Savage.