Sherlock Holmes is missing, and the streets of London are awash with crime. Who will save the day? The Baker Street Irregulars - a gang of street kids hired by Sherlock himself to help solve cases. Now they must band together to prove not only that Sherlock is not dead but also to find the mayor's missing daughter, untangle a murder mystery from their own past, and face the masked criminal mastermind behind it all - a bandit who just may be the brilliant evil Moriarty, the man who killed Sherlock himself! Can a group of orphans, pickpockets, inventors and artists rescue the people of London? The game is afoot!
The Baker Street Irregulars move into 221B Baker Street when Sherlock Holmes goes missing, and agree to help Eliza Mayhew find her grandfather, the Lord Mayor of London.
When an early painting by Constable is stolen from a private collector, four English children decide to solve the crime.
When a phantom begins scaring people at the Theatre Royal, the Baker Street Irregulars must decide if events have anything to do with three terracotta lions that have arrived from China at the British Museum.
When a ghost starts haunting Sir Jasper's family home, four young sleuths investigate a crime from the past and a crime they anticipate.