The Gatekeepers 3-Volume Paperback Set: Raven's Gate / Evil Star / Nightrise

"The Power of Five (also known as The Gatekeepers in the US) is a series of fantasy and suspense novels, written by British author Anthony Horowitz. Four installments have been published to date but another one is to be released. The author has stated on his official website that he is aiming for a 200,000 word book for the final novel and that it could "take years" to write. On his website he stated that he had been researching global warming for the last book in the Power of Five series.[1] The series is published in the UK by Walker Books Ltd and in the United States by Scholastic Press."