Although young Montague Mad-Rat lives in--or rather, under--New York
City, he know very few rats besides his mother, who makes hats, his
father, who builds mud castles, and his globe-trotting Aunt Elizabeth.
But Montague's life takes an abrupt turn for the eventful the stormy day
he meets Isabel Moberly-Rat on his way home from Central Park.
Home, for Montague, is an old sewer pipe. He now learns that there is a
cityful of other rats out there who inhabit abandoned piers and lead
considerably less eccentric and more luxurious lives than his family.
What's more, these rats are in the midst of a grave crises. A human
being has decided to turn their piers into parking lots, and an
extermination campaign is already under way.
As Montague stumbles into this wider, bewildering world, he long to help
ratdom (and impress Isabel). But what can he do, when his only talent is
painting the seashells his Aunt Elizabeth brings him from her travels?
And to make matters worse, it turns out that a drunken uncle of his,
Montague Mad-Rat the Elder, has made their name a standing joke in the
rat world. For the first time in his life, young Montague finds out what
it is to feel helpless and alone--little realizing that he has not only
Isabel and his seashells on his side but his despised drunken uncle as
well.