Future Boy Conan (1978)

In the year 2008, humanity faces extinction due to the effects of its own use of magnetic weapons during World War III. A group of survivors attempted to flee to outer space, but their spaceships were forced back on Earth and crash-landed on a small island. They named their new home Remnant Island. In 2016, the baby boy Conan is born on the island. Several years later, Conan and his adoptive grandfather are the last surviving members of its population. While walking on the beach, Conan finds and rescues an unconscious girl named Lana. She is hunted by the industrial community of Industria, who soon invade Remnant Island. Conan sails alone in an effort to re-locate and rescue Lana from her captors.