An experimental drug that is supposed to reduce aggression has the opposite effect on a baboon that is being experimented on by a group of medical students and their professor. While they are playing a fantasy role-playing game in their research facility, the baboon escapes and begins hunting them down.
When a mysterious virus created by a Japanese doctor in Tokyo escapes containment, the world spirals into chaos. A medical anomaly quickly mutates into a global phenomenon-manifesting in eerie, unpredictable forms across two continents.