Norby Finds a Villain

Rating:
Summary: The 6th book in the SF series for youth.
Review: This is the sixth book in the humorous Norby science fiction series for children about a space cadet and his unusual robot named Norby. A criminal from Earth has escaped into hyperspace and exploded a bomb that opens a "door" to another universe. Jeff and Norby, with their friends, have to travel through hyperspace and time to change history back to its original path. Malevolent beings from the other universe have entered through the door and take over our universe. Jeff and Norby strive to change history so this doesn't occur.