My Teacher Fried My Brains

The first day of seventh grade is probably the worst day of Duncan Dougal's life. He knows that things are really bad when he finds an alien's hand in a Dumpster and then gets plugged into an alien brain fryer!
Can Duncan find out which of the four new teachers in his school is an alien before his brains get fried to a pulp -- or before the aliens try to fry the whole planet?