In The Only Ones, there is Martin. He lives with his father on an island where people come to vacation. Martin and his dad are building a machine with an unknown purpose. Then his father has to go to the mainland. Martin's dad says he'll be back by Martin's eleventh birthday. And his promise holds true. On the day of Martin's birthday, the boat his father took comes into view. Martin swims to it in excitement, but nobody is in it. Martin stays on the island for a year more, then decides he should go to the mainland. There he finds Xibalba, the place for everyone who is left on Earth. It's up to Martin to find a way to bring the people he loves back to Earth.
This book is really interesting. I think that the author could have described Nigel (if you read this book you'll understand) better. He is a bigger character in the story, but you never really know him. I loved this book because it just held my attention for the longest time (well, unit I finished it). This is a definite read for anyone, especially if you love science fiction.