Zack McGee has his arm in a sling. He crashed his bike. All because his four-inch-tall alien houseguest, Amp, stole his brakes! Now Zack's stuck at home with his annoying little brother, Taylor. And Taylor's eager to figure out exactly what Zack has been hiding in his pocket.Like every book in the Alien in My Pocket series, On Impact! mixes Common Core–aligned science and safe, hands-on experiments with hilarious stories that young readers will love.