Giant radioactive beavers and water rats threaten mankind! Yes. That's the plot.
Barney Colrayn is a sanitation inspector in East Anglia with the thankless job of ensuring that big companies adhere to laws against illegally dumping toxic waste into the environment. He takes his job very seriously, and is unforgiving in his leveling of fines and punishments against companies that break the law. Consequently, he isn't very popular with the people he inspects (think Donald Sutherland's character in Invasion of the Body Snatchers).
One company on Colrayn's inspection route in particular is a frequent offender. Jasper Leroy Inc. and its eponymous owner really, really don't like obeying the law and will find any means they can to avoid following the rules and properly dispose of their waste byproducts, because proper disposal costs money Mr. Leroy doesn't want to spend and it's easier to just dump it in the river. Despite all his efforts, Colrayn has never been able to persuade the corporation to do the right thing, and so deep are Mr. Leroy's pockets that any fines he levels at them amount to a slap on the wrist.
But mother nature may soon have the last laugh. Although initially it was merely oil that Leroy Inc. dumped, now radioactive chemicals are finding their way into the river and contaminating the ecosystem. Although it kills all the fish in the river, the native beavers and rats thrive on it, growing bigger and bigger and bigger. And with this increased size comes an increased appetite. And with all the fish they normally eat dead, the huge rodents will have to turn to... something else. Worse, their mutation has given them the powers of ESP, including the ability to will themselves from place to place, attacking unpredictably.
Together with his old friend Edward Sinclair, the local police force and a group of Territorials (army reservists), Colrayn must find a means of stopping the killer beavers before they can Take Over the World.
Tropes used in this novel:
- Absent-Minded Professor: Septimus Harbottle
- Attack of the 50-Foot Whatever: Giant. Beavers. That can teleport!
- Cool Car: The Sinclair saloon.
- Corrupt Corporate Executive: The thoroughly unpleasant Jasper Leroy.
- Eccentric Millionaire: Edward Sinclair. He styles himself as "a Special Agent and Private Investigator," plays Mozart on a grand piano for fun, drives a customized saloon with a modified engine that he personally calibrated, and solves mysteries out of pure boredom.
- Green Aesop: Give a hoot. Please don't pollute. Or else giant beavers will eat you.
- Improbable Infant Survival: Little Ricky O'Jordon is the beavers' first victim. It turns out he's being kept alive inside the beavers' lair. Sinclair rescues him.
- In-Series Nickname: The Territorials are referred to as "Terriers."
- Mega-Corp: Jasper Leroy Inc. According to Colrayn, the company and its various subsidiaries exist only to fill the "already overstuffed" bank accounts of Leroy himself.
- No Name Given: The Terrier captain and the police sergeant.
- Nuclear Nasty: Radiation caused the giant rodent problem.
- One Steve Limit: Averted. Both Harbottle and Reverend Brown have the first name Septimus, whilst both Ricky's mother and Billy the barge captain's wife are named Lucy.
- Rodents of Unusual Size: Did we mention it's about giant killer beavers...?
- Stock Unsolved Mysteries: Whilst they're searching for the missing Ricky O'Jordon, the sergeant brings up Benjamin Bathurst.
- Super Drowning Skills: The crew of the barge. Despite being in a profession that requires them to sail up and down the river, Billy, his wife Lucy and their deckhand (whose name alternates between being John and Tom) can't swim and drown when a giant beaver sinks their vessel.
- Teleportation: The beavers are telekinetic and can will themselves mentally from place to place, effectively allowing them to just poof in, attack people, and then poof back out before the authorities arrive.