Discover the adventure and danger at the heart of the BIONICLE saga! This collection includes the first 4 books in the Bionicle Adventures collection and a bonus mask! The city of Metru Nui is divided into six parts. Each part has a guardian--a Toa--who watches over the Matoran who live there. However, something strange is happening: Matoran are vanishing and a mysterious plant is destroying the city peice by piece. The Toa have to stop the disappearances and find a way to save their city. Do they have the skills to solve this mystery? Or will they finally meet their match?