The Sleepwalkers hunt the nightmares that haunt sleeping minds. They traverse the connected dreamworlds where reason is banished and the imagination holds sway.

But tonight, one Sleepwalker has gone rogue. Abandoning her oath to protect the dreamscapes, she devotes herself to another cause, threatening to unleash a nightmare older than man

Once a feted musician, Manderlay lives in an Edinburgh care home, riddled with arthritis. He longs for his youth and the open seas, to regain the use of his hands and play the violin again.

For too long, Manderlay's nights have been host to dark, corrupted dreams. His comrades in the retirement home fear Manderlay is giving in to age and senility - but the truth is much worse. The dreamworld is mapped with music – and one of Manderlay's forgotten compositions holds the key to an ancient secret. The Sleepwalkers are closing in on him. He might be their saviour, or his music might be their damnation...