Wild Boy by Rob Lloyd Jones

Wild Boy is totally covered in fur. He's beaten and abused as a circus freak and finally decides to escape. He meets an acrobat, Clarissa, before leaving and helps her rob one of the circus visitors. However, they only manage to steal a note from him and the man is later found murdered. The note talks about a powerful machine, and a masked man threatens them for information. He frames Wild Boy and Clarissa for two murders, so the two freaks go into hiding. They gave two choices. They can continue to live in the sewers, or they can solve the murders and clear their names. They discover it's almost impossible to find clues when there's a huge reward for their arrest, and every policeman in London is searching for them.

Wild Boy and Clarissa are wonderful characters. Wild Boy frightens everyone he meets, but he is able to notice tiny details and is able to solve mysteries. He's like a young, freakish Sherlock Holmes, but he lacks confidence in himself. On the other hand, Clarissa is pretty and agile, and she has a hot temper. She's very impulsive and has confidence in her physical abilities. Wild Boy and Clarissa hate each other, but they combine their talents to make a remarkable detective team. The plot is full of adventure, as the characters try to stay alive and out of jail. It ends in a climax where Wild Boy puts all of the clues together to catch a killer.