The Incredible Tide is a post-apocalyptic science fiction novel written by Alexander Key, published in 1970. It was the inspiration for the Japanese animated television series Future Boy Conan (未来少年コナン Mirai Shōnen Konan), directed by Hayao Miyazaki.
The Incredible Tide tells the story of Conan, a boy who lives alone on a small island on Earth ravaged by World War III. The world was knocked off its axis and the continents have sunk into the ocean, with only small islets remaining. Conan is rescued but finds that the new society is very different from the world he knew before.
The seabirds, Conan’s only friends, aroused him at dawn by screaming and dropping pebbles on his hut. He crawled out eagerly and raced down to the narrow beach, sure that a school of fish had entered one of his tidal traps. The birds always called him like this when fish had been caught. But the traps, he soon found, were empty — and still the gulls and terns wheeled about him, making a great racket.
What were they trying to tell him?
He turned and ran up the steps to the highest point of his rocky islet, and climbed upon the stone platform he had built long ago. A quick look around showed only emptiness, save for the two smaller islets of the group, dim in the distance on either side. They bounded his world. Beyond them, and all around in the mist-haunted sea, nothing was visible, not even the horizon.
“What do you see, Tikki?” he asked, as a slenderwinged tern circled close, giving quick little twitterings as if trying to speak. “Where is it? Show me!”
The tern brushed his lean cheek with its pinions, wheeled high, and shot away in the direction of the eastern islet. Several of the other birds followed. Conan watched until they were fading specks in the mist. Something was out there, surely, but it was far beyond the islet and invisible from here. A whale? No, a school of whales, most likely. Nothing else could cause such a stir among his friends. There wasn’t anything else in existence that was big enough or unusual enough.
Or was there?
Conan gave a little shake of his tawny head and slumped down on the platform, hugging his knees in sudden misery. To judge from the evidence, there was very lit- tle left on the planet but water. As for people, if many remained after what had hap- pened, most of them were probably castaways like himself. In the years since the last fleeing helicopter had crashed in that incredible tide, breaking apart and flinging him alone into the darkness, he hadn’t seen or heard a craft of any kind, air or sea, nor had he even spotted so much as a vapor trail or a gleam of light. Was he the only per- son left? But of course he wasn’t. He had proof that Lanna was safe…
The book is available here in PDF, or maybe you want to buy it on Amazon.