When Erik Torvald, a licensed digger of geoduck clams, is found unconscious and dying of a massive dose of red tide toxin, Peyton McKean is called upon to use his prodigious intellect and his biotechnological genius to solve an unprecedented mystery. Did Torvald die of a surfeit of clams or, given the impossibly huge quantities of toxin in his bloodstream, was he poisoned? If so, how? And by whom? Peyton McKean and his pal Fin Morton pursue the matter along a twisted path of clues and suspicious characters. Was it the Native American shaman with a grudge against modern culture? Or was it another geoduck fisherman with ties to criminals and drug dealers? McKean pursues the case, but along the way someone begins to pursue him. Will he solve the mystery or become the next victim of the Blood Tide?