Hideous Night

Celine Dubois is a brilliant scientist working on advanced scientific research into the foundations of reality. A committed lesbian, she is based at CERN in Switzerland and is brusque, dedicated, efficient and definitely does not "suffer fools gladly". Then one day, two very strange things happen to disturb her self-assurance.
Firstly, she opens an e-mail from a disgraced former physicist that informs her that "Earth is a farm" and all humans are the prey of a race of invisible parasites that infest them and cause degenerative diseases. Naturally, she disregards it.
Secondly, at a meeting she hears one of her junior colleagues relate how his staff are reporting mysterious events, which some of them refer to as "seeing ghosts." Ordered to investigate this claim Dubois is at first dismissive but then herself encounters the inexplicable phenomenon of a column of grey mist that seems to be trying to entrap her. And yet she can find no evidence on the CCTV that it existed.
Later, both Dubois and Hilda, her girlfriend, realise that they are both suffering from different forms of autoimmune illness.
Afterwards, Dubois has a meeting with the physicist who sent the peculiar e-mail. He is Marius Larsen, a physically imposing Norwegian who was sacked after a failed experiment involving a powerful laser. Larsen claims a side-effect of that accident, which apparently killed his friend, is that he can now see the parasites - which call themselves "hran". Dubois has him thrown out.
Dubois and partner are promoted to take part in research using a new, very powerful particle collider in Japan. However, this facility also reports inexplicable happenings in which people are vanishing without trace. Dubois finds that Larsen has followed her there and is still peddling his claims. Both Larsen and Hilda go missing.
She discovers that she has been transported to a ruined Earth some centuries on from her time. After being held captive by some degenerate humans, she is eventually rescued by the agents of an entity called "Kewfor."
Reunited with both Larsen and Hilda in Kewfor's citadel she learns the horrific truth: the hran are very real and their subjugation of humanity has only just begun. All three must cross to the realm of the hran in a desperate, final attempt to defeat the parasites and reclaim the Earth.