Episode One Synopsis (SPOILERS!)

As her personal life lies in ruins, British doctor Amy Sparrow is accosted by secret American agents and persuaded to join a foreign legion of dedicated doctors at an undisclosed location. Only this is no ordinary hospital; this one treats aliens injured in an intergalactic war. Whilst Dr. Sparrow meets new colleagues and observes the unfamiliar practices, a dangerous creature kills a member of staff in the basement.

Main boss Nicolas Kazan wants the murder covered up but head-strong Dr. Eve Heller agrees with several troops that they need to keep an eye out for danger. Sparrow ends up helping in an emergency and then becomes the target of affections by a tiny fluffy creature known as a Crawler.

Annoyed by Heller's bossy ways, other staff members approach Kazan with a formal complaint. When a deadly Hostile alien is found by troop Rodrigo in the hospital grounds, Heller leads the staff in an offensive before back-up troops arrive. Rodrigo is severely injured and Sparrow, concerned that other people might get hurt, pursues and kills the alien.

Heller is blamed for what happened to Rodrigo and Sparrow suffers nightmares as she naps in an exam room. Sparrow later speculates with Heller that the Hostiles may have been present in the hospital all along. In a secret underground level, scientists monitor more Hostile aliens under Kazan's watchful gaze.