In 2011 a small village in South America is attacked by unknown creatures. Upon inspecting the survivors, a new type of hook worm is discovered and classified as "Alpha-worm". These parasites cannot be countered with any known medicine and spread through the blood stream of their victims, rewriting their genetic code and turning them into much stronger monsters. They escaped the research facility and the situation quickly became uncontainable, resulting in the drop of an atomic bomb on the site. Since then there have been several contained outbreaks all over the world which have all been stopped by the G.U.I.D.E.-squad, a special forces unit consisting of Ninjas especially trained for these outbreaks.