Seventeen-year-old Prenna James emigrated to New York when she was twelve. But Prenna didn't come from a different country, she came from a different time - a future where a mosquito-borne illness has mutated into a pandemic, killing millions and leaving the world in ruins.

Prenna and the others who escaped to the present day must follow a strict set of rules: never reveal where they're from, never interfere with history, and never, ever be intimate with anyone outside their community. Prenna does as she's told, believing she can help prevent the plague that will one day ravage the earth and take the lives of her younger brothers. But everything changes when she falls for Ethan.

She might be able to save the world ... if she lets go of the one thing she's found to hold on to.

This book has been graded for interest at 12-18 years.

There are 320 pages in this book. This book was published 2015 by Hodder & Stoughton General Division .

Ann Brashares is the author of four bestselling young adult novels. This is her first novel for adults. She lives in Manhattan and spends her summers on Fire Island, New York.