Whenever a normally meek Bay Region insurance agent instantly turns into a voracious, homicidal maniac with an uncontrollable appetite, doctors quickly determine that the cause must be a mind parasite that may only be extra-terrestrial. Now, San Francisco Law enforcement Detectives Karen Hall and Yuri Markov are on a mission to end this influx of assault before more people become contaminated. But at every change their investigation appears to be hindered by shadowy federal agents with a concealed agenda. Can they stop this reign of terror before one of these becomes the next Symbiote?