Duckula decides he wants to become a famous detective, like Sherlock Holmes, so he, Nanny, and Igor travel to London.

Von Goosewing plans to use a growth formula to grow a huge clove of garlic next to the castle to kill Duckula. He spills some on Duckula's broccoli by accident and it grows, carrying castle Duckula and its inhabitants to a castle in the clouds that is owned by a giant.

A local TV station is making a documentary about Castle Duckula and the Count. Unfortunately, they don't think Duckula is scary enough, so they make Igor play the part of the Count.