Jacob Singer is a divorced Vietnam veteran living in New York. Though well educated, he works as a mail man and has become romantically involved with Jezzie, one of his co-workers.
He is haunted painful memories, one is a horrible Vietnam battle experience when he was nearly killed by a soldier with a bayonet, though he can't clearly recall the details. The other is the death of his son.
Jacob's tenuous hold on reality starts to slip as he begins seeing visions of monsters and demons all around him; closed subway stations take on a creepy life of their own; a crowded party turns into a room full of winged demons; a train full of strangers look as though they have sprouted tails and horns. He suffers severe panic attacks related to the chaos that may be reality, or may exist only in his mind. Jacob seeks counsel from Louis, a kindly chiropractor, as his ex-wife Sarah, fellow Vietnam vet Paul, and enigmatic stranger Michael all try to help the tortured Jacob.