Dan Dark, an unsuccessful and bedridden novelist with a crippling disease, begins to mentally rewrite one of his novels, "The Singing Detective," with himself in the leading role. He drifts off into a fantasy world set in 1945 with spies, criminals and '40s music. Under the care of the eccentric Dr. Gibbon--who slowly aids the despairing Dark to use his imagination and its creations as a bridge into himself--the mental voyage ends up becoming the key to conquering his illness.