From The Back of The Book
Two Twins, One Eyeball, No Surrender
Pet has long endured the trickery of its mischievous masters, Edgar and Ellen, but no more! The one-eyed creature has newfound strength, willpower, and a plan that could tear the twins apart. Meanwhile, the Knightleighs have invaded the twins' house, and Edgar and Ellen are worried -- not until Ellen starts acting very oddly. She's tidying the house and taking baths. She's even accepted an invitation to a slumber party hosted by archrival Stephanie Knightleigh! Surely she's got a scheme up her (unusually clean) sleeve. Or has a hairy traitor managed to break up the devious duo for good?
Edgar and Ellen have been tormenting their pet, Pet, forever, but when Ellen changes from a mischievous trickster to an apple-polishing ninny overnight, no one suspects Pet is behind the whole thing. Now Edgar must wage the war of a lifetime by himself: Mayor Knightleigh’s wife Judith wants to remodel the twins' dank house on live TV, and she has recruited an army of helpers to get the job done, including her daughter, Stephanie, the transformed Ellen, and an array of handymen from gardening policemen to a cage-cleaning zookeeper. Edgar’s plans to stop this house metamorphosis are stymied at every turn by his turncoat sister—but he loses all hope for her when he witnesses her going to archenemy Stephanie's for a sleepover. He finds a cure for her—and a way to repel the invading army—but not before learning that Pet's tears is a stronger version of the balm, the balm in turn has the power to transform people into human gumdrops like his super-sweet sister. The twins are left with the unsettling realization that Pet has motives of its own, is an old friend of the towns founder Augustus Nod, as well as a possible alliance with their creepy caretaker, Heimertz.