A man, Mr. Vandercamp, walks into the Vitas Petrol office building. He has a bloody nose and within a few minutes collapses on the floor and dies. His body shrivels up and spews blood at the crowd of employees gathering around his dead body.
Agent Dunham and Peter arrive at Vitas. They learn that Vandercamp didn’t know anyone at Vitas.
Mike, a courier who rode up elevator with Vandercamp, is showing signs of infection because his nose begins to bleed.
Walter, Astrid, and Broyles arrive at Vitas just as Mike is attempting to leave the building. Walter stops him from opening the door just in time and he dies on the other side of the glass door. The building must now be quarantined.
The Center for Disease Control is contacted and soon arrives. Walter asks Peter to be careful. Agent Dunham begins to notify the Vitas employees of the quarantine and separates them into groups that were in contact with the infected men.
A receptionist shows sign of infection and Peter asks her to lie down in an isolated office. Agent Dunham next questions a man, Mr. Aims, on why he had a meeting scheduled with Vandercamp. She learns that Vandercamp was there to discuss their competitor’s oil prices. Vandercamp was an oil consultant.
Walter and Astrid are back at lab trying to isolate the virus. He believes virus is not airborne, because more people would be showing signs of infection.
The infected receptionist walks out, screams, and throws herself out the window. Peter gets scared and falls on Vandercamp’s dead body. He gets blood all over himself and now might be infected with the deadly virus. Fearing infection Peter goes through Vandercamp’s pockets and finds car keys. In his car they locate his briefcase.
Walter figures the virus wants to get out of the building, causing the receptionist to jump through the window to her death. It wants to get outside to spread to others. Creepy!
In Vander briefcase they find a drill core sample from an exploratory oil drill. That is the origin of the virus. The core sample was taken from 10 miles down the earth’s surface, and this 75,000 year old virus is responsible for wiping out the ice age mammals!
Peter begins to bleed from his nose. Walter and Astrid arrive and start testing Vitas employees to see who is infected, allowing those uninfected by the virus to leave. Agent Dunham is not affected. Peter switched his swab to not show his infection, so he could leave and begin spreading the virus to others. Two agents notice that Peter is bleeding from his nose and stop him from leaving the building just in time.
Agent Dunham calls Walter and Astrid and tells them Peter is infected. The army is authorized to move in, contain, and eliminate those infected with the virus.
Walter will not leave Vitas because he is determined to come up with a cure, especially for his son. Astrid stays to help. Walter, being as intelligent as he is, figures out that ash from a volcano irruption originally blocked the sun in prehistoric times. He believes the sulfuric acid in the ash must have killed the original virus. Good job Walter!
Of course, Walter was right and he figured out the cure. Now they race against time to create the medicine to save Peter, before the army begins to terminate the infected.
Peter and the infected are now forcefully trying to get out if the building. Olivia agrees to go into the building and turn on the ventilation system so a gas, Fentanyl, can be used to knock out the people and buy them time. Peter attacks Olivia and steals her gun. Olivia manages to turn on the vents just in time. Walter injects Peter with the cure, and saves his son.
Astrid asks Walter what he meant when he said he couldn’t let Peter die again and he responds that some things are better left alone.