Incurably nosey Lucy Harlow takes a job as a PA to David Black, the owner of a specialist engineering firm, and lands in a small office taut with sexual tension. Beautiful but bitter secretary Rachel Owen is obsessed with Black and is already jealous of Lucy. But there's something more sinister than unrequited love, with David refusing to travel, leaving the customer interface to a man he clearly finds distasteful, his technical director, Bill Turner. When David asks Lucy to babysit for him and his wife Miriam, Lucy takes the opportunity to find out what's going on. She discovers a disturbing photograph of a naked Miriam in a wallet in David's jacket, but little does she realise that it will set her on the trail of a serial killer...Oxygen Restriction is a story of fetish and murder, and is the first case for budding young sleuth Lucy Harlow.