It's been 200 years since the most famous detective of all, Sherlock Holmes, stalked criminals through the streets of London. Now Sherlock is back in the guise of his great(x10)-grandson, twelve-year old Unlock Holmes. When Unlock's parents disappear from their Penthouse Apartment, Unlock is forced to move in with his Aunt Kathy, better known as Mrs. Hudson. She lives in a modest pod on Bakersfield Avenue but within two weeks of Unlock's arrival, the street's name is shortened to Baker and her number changed to 221B.