Celine Dubois is a brilliant scientist working at the CERN research establishment in Geneva. She doesn't suffer fools gladly and is unimpressed when Marius Larsen arrives at her office, telling a wild, unbelievable story.
He believes that humanity is the helpless prey of a deadly race of invisible parasites that emanate from another plane of reality. These creatures infest humans and are responsible for many of the degenerative diseases which afflict us.
She kicks him out, but then a series of strange events slowly convince her that there is something in his story.
Eventually when confronted with an horrific truth, she and Larsen must cross the dimensional planes in a mission of unparalleled danger - to face down the parasites in their own realm.