The Devil Inside (Shadowless 3)

Running out of air.
The lights are failing.
Something has gotten inside...

Depravity has set its sight upon mankind's remaining survivors. Blood smears stain the once bright light panels that keep them safe from the darklings. One of them is possessed by the creature, but nobody knows who--and they won't have time to find out with the oxygen recyclers damaged and failing.

One man might be immune to being possessed by the demonic entities... but can the community really send Ricky, a man with Downs Syndrome and a crippling fear of the dark outside in the night in the hopes of salvation?

Be Afraid of the Dark.