When extraterrestrial woodchucks attack, ten-year-old Jimmy, his two-and-a-half-year-old sister, friend William, and an eccentric classmate who has built a flying saucer in her Manhattan brownstone, join forces to save the universe.
Edgar, an eleven-year-old orphan, finds a book that reveals significant secrets about Atherton, the strictly divided world on which he lives, even as geological changes threaten to shift the power structure that allows an elite few to live off the labor of others.
Thirteen-year-old Atticus "Tick" Higginbottom begins receiving mysterious letters from around the world signed only "M.G.," and the clues contained therein lead him on a journey to the perilous 13th Reality and a confrontation with evil Mistress Jane.
In an overpopulated world where all signs of nature have been obliterated and a wall has been erected to keep out plague-ridden animals, twelve-year-old Mika refuses to believe that his twin sister was killed after being abducted, and continues to search for her in spite of the dangers he faces in doing so.
When her mother is abducted by aliens on Christmas Eve (or "Smekday" Eve since the Boov invasion), 11 year-old Tip hops in the family car and heads south to find her and meets an alien Boov mechanic who agrees to help her and save the planet from disaster.
Stranded on the moon after his extraordinary airplane takes him into outer space, a boy meets a marooned young Martian with a broken spacecraft, and the two new friends work together to return to their respective homes.