On a dare from her fellow street urchins, 14-year-old Wiggins tries to pickpocket a strange old man. Not only is Wiggins unsuccessful, but the old man, who is actually Sherlock Holmes in disguise, manages to take the gold ring that was in Wiggins’ pocket and leave behind a note directing her where to go to get it back. When Wiggins goes to 221B Baker Street to retrieve the ring, she is shocked to find out how much Holmes knows about her based on a quick observation. After Wiggins sees Holmes use the ring to solve a case, Wiggins proposes to work as his assistant. Intrigued by her potential, Holmes agrees to begin training Wiggins on a trial basis, so long as she helps Mrs. Hudson with the chores. Wiggins and Holmes must learn to trust each other as Wiggins and her group of street urchins help him solve two dangerous mysteries: The Red Headed League and The Adventure of the Blue Carbuncle.