As on earth, there were monsters on the undiscovered planet that John Lyon (young, Kansas City history professor) had found a time/space way to reach. A place with a Medieval culture that he'd dubbed Band World. Becoming Mage of the Band country of Stil-de-grain, he was expected to solve "his" country's problems. His weapons? A Magical Crystal he'd found, supplemented by simple modifications of Earth's 20th Century know-how. Problems. Like John's people calling upon him to kill a monstrous, undersea creature that was "eating" ships at the mouth of Stil-de-grain's major harbor. In this instance—John remembering how to make black powder—he was going to use this early form of gunpowder to shoot a "whaling" spear into the creature... It was just that when a non-scientist starts fooling with gunpowder, the result could prove to be an "explosive combination!"