The overnight ER rotation at Springer Hospital is a calm one， which suits Dr. Toby Harper just fine. While Toby is fiercely proud of the stripes she earned as a resident in a big-city ER， she s come to appreciate the pace at Springer. But no hospital could have been prepared for the man Toby admits one quiet night. Delirious and in critical condition from a possible viral infection of the brain， he barely responds to treatment. And then he disappears without a trace. Under fire from the hospital administration for literally losing a patient， and fearful that she s missed a life-threatening diagnosis， Toby knows she must find the patient. Her hunt is intensified when a second delirious patient dies in the hospital s care. But even more chilling is the discovery that the infection can only be spread through direct tissue exchange.