Diamond Chaos - Paul Cunningham - Bog

John and Zack are good friends, but it takes a real friend to lay each other's lives on the line at the same time. London was always a quiet, cozy city, but these dark figures running around town causing chaos are keeping John and Zack on their toes. John has just become a detective. His friend Zack has agreed to help him, but will they both be able to stand up to the dark forces challenging their lives?