Face Not Seen

Martin Russell spends his last £2 coin on a bus ride out of the city with barely enough motivation to face the future. Then a chance incident near his home triggers a sequence of positive opportunities for him. His life, unexpectedly, could not be better.
That is, until the phone call informing him his friend Hannah has disappeared, and people's lives will now change forever.
And who can be trusted? Certainly not the obsessive Nash, or the slimy underworld figure they call The Chemist.
How about John Staples, better known as Pin-up? Is his renewed friendship with Martin genuine or suspicious?
What's going on with Zachary and Bobby? One's a schoolboy drug dealer, the other is a disgraced ex-copper. What could they possibly have in common?

Why are their intertwined stories entitled A Face Not Seen? For the answer to that question, you would have to ask Xenon. But that's a problem, because no-one in their right mind ever questions Xenon...