The Legacy of Heorot
Some people escape to the space ship. But, other stay to defend the town. They use the electric fences and land mines and guns to kill the little Grendels. After awhile the town gets too damaged to protect anymore. The people run away to a cave on a mountain. The Grendels follow them up a river and attack the cave. The people use kerosene to burn the Grendels. Also, they knock big rocks down onto them. After enough Grendels get killed, the other Grendels learn to run away instead of just attack. The people win.