To country mouse Madeleine and Oxford-bred Marcus Aurelius there is born a giant, ravenous baby, whom they wisely/learnedly name Magnus. Fed, in desperation, the Porker Pills unlettered Madeleine inadvertently ate when she was pregnant, Magnus grows bigger, more demanding ("More, Mummy! More! More!")--a trial to his meek, magniloquent father, a worry to his loving and practical mother. With the Porker Pills used up, and fierce Magnus in danger at loose, the two appeal to farmer-fed rabbit Roland--who fancies being called "Uncle" by "the little fellow," then greets word of his giantism with "How perfectly splendid!" The three are ecstatic at Magnus' triumph over a "Nasty cat." ("A positive powerhouse? booms Roland. "Powermouse, you means," squeals Madeleine.) Even Marcus Aurelius expresses his "undying gratitude" at Magnus' springing him from a trap. Then the farmer, noticing the empty rabbit-food bag, the sprung trap, sends for Jim the ratcatcher--behind his back, Jim the Rat. . . and an authorial upending the equal of Magnus. Jim the Rat can smell a mouse (even "a house-mouse'); he treasures the legend of the King Rat--"Could it be a King Mouse?" Baiting a mink trap with a Mars Bar, he catches Magnus; covertly bears him off-to the horror of the watching trio; and sets about taming him--"The way to the royal heart, he thought, is through the royal stomach"--while Madeleine and Marcus Aurelius comfort themselves with Roland's kindly prophecy of his "triumphal return." So, indeed, it will be: Jim's worship of his extraordinary pet ("A ratcatcher may look at a King Mouse") is matched by Magnus' guilty yearning ("All because Magnus was so greedy! Nasty, nasty Magnus!") for his Mummy and Daddy. There is a hint, once they're all happily resettled, of further adventures to come. A disquieting hint, in a way--so vigorously and unexpectedly do the animal world and the human world mingle in this first.