There's a dead body under Hayley's bed.

She can smell it. Touch it. 
Her husband can't see it. He thinks she's having a nightmare. Her therapist believes it's the trauma of the car accident. And Hayley doesn't believe in ghosts.
But with every day that passes, the vile stench of death gets worse.
Who is this rotting woman?
Why is she under Hayley's bed? 
And more, importantly... 
Who killed her?