In the stinking mud of a great tidal river, a body lies half submerged.
Sir Tommy Best, adored British actor, has fallen to his death through a hole in the walkway above.
The saintly Sir Tommy was friend to the starving and penniless, to kings and stars.
He was also totally blind and reliant on his brilliant guide dog, Suzy.
But she is nowhere to be found. It seems unimaginable that Suzy would have led him into danger, so is it murder? And where is she? When she finally turns up, it is only to deepen the mystery.
She is stressed and tense and soon Chief Superintendent 'Fatso' and Detective Chief Inspector Ned realise that only one person in the force can possibly help.
Kate, police dog handler extraordinaire, known affectionately as the Dog Tart, suggests they find Nick Parsons, who trained Suzy, in the hope that he can get the dog to lead them to the truth.
The search for Nick Parsons culminates in a highly unusual plan, in which Ned will become blind for one night and with Suzy the guide dog, re-enact Sir Tommy Best's last fateful walk.
The truth which they uncover is utterly horrible.