The Kidnapper's Accomplice, Paperback/C. J. Archer

To investigate the source of gossip about Cyclops, Willie does the unthinkable - she dons a dress. However her plan goes awry when she's kidnapped by a disgruntled magician with the power to detonate gunpowder at will. The magician forces India and Matt to race all over London in the hunt for her before the bombs go off. Meanwhile, powerful members of the Collectors Club are trying to find out what new spell India has created with Fabian, and with India's attention focused elsewhere, they might just succeed.