Plot Summary

A mysterious catastrophe unfolds when a space shuttle disintegrates in the sky, scattering debris from Dallas to Washington. Although authorities quickly regain control, unsettling rumors begin to spread about an unknown substance clinging to the wreckage—one capable of surviving both the freezing vacuum of space and the extreme heat of atmospheric re-entry. Those who come into contact with it are the first to change.

In Washington, psychiatrist Carol Bennell (Nicole Kidman) initially dismisses the incident as unrelated to the strange behavior she begins witnessing around her. Patients claim their spouses are no longer themselves, sudden outbreaks of violence are swiftly silenced, and her son’s Halloween basket brings home something disturbingly alive. Public officials insist there is no reason for panic, attributing everything to a new strain of flu.

As events escalate, Carol confides in her colleague Ben Driscoll (Daniel Craig), sensing that something far more dangerous is unfolding beneath the calm surface. Even as warnings mount, she allows her son to spend the weekend with his father, a senior official at the Centers for Disease Control who is directly involved in investigating the incident.

With the spread accelerating, Carol uncovers the horrifying truth: the so-called cure is actually facilitating an alien cellular invasion. Attacking human DNA during sleep, the organism replaces its host with an emotionless duplicate—identical in appearance and voice, yet stripped of all human feeling.

Forced into a transformed world where calmness is a disguise and sleep means surrender, Carol embarks on a desperate journey to survive and save her child. To remain human, she must hide among the changed, suppress her emotions, and above all, stay awake.