The good thieves / Katherine Rundell ; illustrated by Matt Saunders.

Vita Marlowe may be small, but she greets New York City as a boxer greets an opponent before a fight: she sets her jaw at it. Fresh off the boat from England, she has a job to do in the city. Her beloved grandfather Jack has been cheated out of his home and possessions by the infamous mafia boss, Victor Zaroff. Seeing Jack's spirit is broken, Vita is frightened and desperate to make him happy again, so she devises a plan to outwit his enemies and recover his fortune. But the plan requires some highly unusual skills and so she sets about finding some highly unusual friends to help her out.