Monsters vs. Aliens: The Junior Novel — Susan Korman

When an alien robot crashes into Earth and creates a wave of chaos, the U.S. government unleashes an unusual weapon -- monsters! Otherwise known as Ginormica, The Missing Link, Dr. Cockroach, Insectosaurus, and B.O.B., the monsters have a chance to win their freedom by saving the world. But the robot is just the beginning. Can the gang stop an alien invasion before the Earth is destroyed?