Many years ago, a crippled spaceship crashlanded on an island on a strange new planet. The survivors have struggled over time to eke out an existence while waiting for rescue. It has been two generations, but still they wait. Four friends, grandchildren of those first refugees, are curious about their island and what might be across the sea. In the past, some of the elders left to explore the planet but none ever returned. Now the remaining leaders think it is too dangerous. The sea hides a strange presence and the friends have no other way to get off the island ...