Five Union prisoners escape from a Confederate prison in a hot-air balloon during the American Civil War, but crash-land on a remote island in the Pacific Ocean. The island, which they name Lincoln Island, is seemingly deserted, but the castaways are determined to survive and create a home for themselves. They explore the island, build shelters, and learn to live off the land. They also discover strange and mysterious phenomena on the island, and they eventually realize that they are not alone. They are hunted by a group of pirates, and they must also contend with a dangerous animal that roams the island. But the castaways are resourceful and determined, and they eventually triumph over their challenges. They build a thriving community on the island, and they live in peace and harmony.