Alien apocalypse, or, Alien busting ninja adventure

Summary: "When hungry aliens begin their 'rain' of terror, break out the umbrellas - the aliens can't eat you with an umbrella shoved in their huge mouths. Looking for yummy human tenders, Admiral Nact-bauk invades the local school. Zack and Zoey lead the counterattack armed with rulers, protractors, and dodge balls. They might have a chance, if Nact-bauk didn't gulp down the only teacher brave enough to stand up to him. Even worse, he forces Zoey onboard the alien vessel for dinner - along with a bucket of honey-mustard sauce. Zack will do just about anything to save her. If Principal Blathers won't help, Zack sees no choice but to 'borrow' the principal's car. Chasing the alien saucers, he meets up with a wrinkly WWII hero who thinks he knows the alien's weakness: electric toothbrushes. Wielding only umbrellas and battery-powered dental weapons, things look grim. Even if the pair manage to rescue Zoey, there's the small matter of escaping a spacecraft flying over two hundred miles an hour. Can you say, Jetpacks?"-- page 4 of cover.