Danny enlists her colleagues to help when her boyfriend, Gabriel, is arrested for being in the country illegally and threatened with deportation. Also, Bull represents a German national who is being sued by a museum over possession of a valuable painting.
With Rory and Ava at odds, Sara tries to come up with a way for them to get along, but all is put on hold when a new magical creature attacks the Legends. Constantine is forced to confront his tragic past but it could have devastating consequences for the rest of the team. Meanwhile, Mona has a crush on someone she works with and gets some advice from Nate.
Marta convalesces as a mysterious illness sweeps through Olympus Town and Lukrum Colony. When IMSF realizes one of its own has died as a result, it races to determine the cause, origin and mode of transmission before time runs out—and more lives are claimed. Back in present day, Vladimir Chuprov, a Greenpeace activist, sheds light on an indigenous health crisis being kept quiet by the Russian state to benefit their Arctic oil endeavors.
Dr. Shaun Murphy and Dr. Audrey Lim treat two patients who collapse at the local airport and whose symptoms point to an infection that may become airborne. The staff races to contain the infection before it spreads to the rest of the patients in the ER.