"When Hyacinth mixes hot and cold water in a sink in London with disastrous results, she learns that the city was built on magical rivers that are now London's sewers--and somehow her family is connected to the magic"--

"Now that Hyacinth Hayward knows about the enchanted rivers under London, she's determined to find out more. Unfortunately, London isn't cooperating. Instead, Hyacinth stumbles on a new adversary--a girl who is trying to steal all the ancient stones that keep the city in balance. A girl with glowing, magical fingers, whose entire body is tattooed with spells. A girl called Minnie Tickle. (What? Were you expecting something more . . . fearsome?) To...