'When a hole in the ground opened up and swallowed my mum, my life changed forever...'

With his mother in hospital in a coma, Griffin has to stay with the uncle and aunt he hasn't seen in years. His cousin Cinnamon doesn't want him there. What's going on? Is it something to do with the fabulous Aztec knife about to go on display in the museum? Is it really cursed? Griffin and Cinnamon will have to find a way to work together to survive when they are lured down into the secret tunnels...