In this novella, Devilly Peen, a writer of detective fiction uses her imaginative skills to solve a series of gruesome murders. She inhabits a mildy dystopian world, a vast agglomeration of plastic waste that circulates gently in the western Pacific Ocean. This is the Great Pacific Gyre. Devilly's approach to solving whodunnits compares to Agatha Christie's Miss Marple. Like her literary predecessor she is tiresomely astute and operates in a world where the venemous denizens of the deep provide an extravagant array of poisons. In contrast to the familiar murder mystery, Devilly Peen, the police and the villains who populate The Gyre are Octopods, a race of eight armed colonists from a distant planet. Devilly is contacted by her old friend Octabel who is worried by threatening letters she has been receiving. Tracking down the killer takes Devilly from her village of Nether Vortex to the mansion of the Clamshucker family in the up-market district of Perrier. Devilly soon learns that Octabel's husband Magnus Clamshucker is a gangster, whose criminal empire is under attack by a mysterious competitor. Various minions die horrific deaths before Devilly, aided by her nephew Police Inspector Moray, penetrate to the very bottom of the matter, suspended above the deep abyss of the ocean.