Sam Appleby wants a sword, but his parents don't believe in violent toys. They try to encourage Sam towards kindly, gentle things like balloons and flowers. Meanwhile the school bully, Hacky Mackie, has a whole arsenal or weapons, and he's planning to use them to catch Buckbounder, the notorious bank robber. But when Sam and Hacky come face-to-face with Buckbounder, Sam finds out there's a lot more bang in a balloon than he ever could have imagined.