At "Area X", a government facility on the southern coast of the US, Lena, a cellular-biology professor and former soldier, is in quarantine. She undergoes a debriefing about a four-month expedition into an anomalous iridescent electromagnetic field dubbed "the Shimmer", of which she and her husband, Kane, are the only survivors. In flashback, Kane, an Army Special Forces soldier, appears in their home after having disappeared on a mission nearly a year ago. He remembers nothing of that time and suddenly falls very ill. A government security force intercepts Kane's ambulance and transports him and Lena to Area X, near where the Shimmer had begun to spread three years earlier..