yo-yo 's weekend while spending a weekend in york , schoolboy yo-yo 's ring is stolen by mr vanilla , a forty stone jewel thief so he gathers together , among others , lily gusset , the reverse drag-artist , mrs lollipop , bed-ridden these forty years , baby the talking blackbird , the custard-pie flinging lettuce brother clowns , an angry ichthyosaur , a weed and a pebble , a copper named kipper , a professional scotchman named wee jocko mctavish and the severed head of the ninth earl of northumberland in a quest to retrieve it .