Every town on Discworld knows the stories about rats and pipers, and Maurice - a street wise tomcat - leads a band of educated ratty friends (and a stupid kid) on a nice little earner. Piper plus rats equals lots and lots of money. Until they run across someones playing a different tune. Now Maurice and his rats must learn a new concept: evil...

When a systems engineer blows the whistle on a dangerous technology, Charlie's Angels from across the globe are called into action, putting their lives on the line to protect society.