Lena (Natalie Portman) is a biologist. One year ago, her husband Kane (Oscar Isaac) mysteriously disappeared after participating in a secret mission. During this year, Lena has been living in sorrow. One day, Kane, who had lost his memory, suddenly appeared in front of Lena, then fainted and was sent to the hospital. There, Lena met Dr. Ventress (Jennifer Jason Leigh). The doctor told Lena that Kane was sent to an unknown area covered by "Flash". In three years, countless teams were sent to explore the area, and only Kane came back alive. Not only that, "Flash" is constantly expanding. In order to find out the truth of the matter, Lena voluntarily joined the next batch of teams to be sent. In addition to Dr. Ventress, she also went with Anya (Gina Rodriguez) and Qiao Xi (Tessa Thompson).