What Abigail did that summer

Aaronovitch's trademark humor is the highlight of his ninth Rivers of London urban fantasy (after False Value). Here, he focuses on London teenager Abigail Kamara, a supporting character in previous books who's occasionally assisted apprentice wizard Peter Grant, a member of a supernatural branch of the Metropolitan Police. Kamara is reintroduced being questioned in a police station. Several teens have recently gone missing in Hampstead Heath, and the authorities are baffled by the disappearances--but Kamara realizes that something paranormal must be going on and sets out to investigate, aided by new friend Simon Fletcher. Her search leads to encounters with talking foxes and pocket dimensions, along with conversations with river spirits descended from the mother spirit of the Thames. The mystery takes some surprising turns, but Aaronovitch makes buy-in to his imagined world easy. His wry humor (an interrogating police officer is described as "stressing her northern accent--going for that no-nonsense Coronation Street mood") keeps things lively, and Kamara is an endearing protagonist who is more than capable of carrying future books. Series fans are sure to enjoy this. Agent: John Berlyne, Zeno Literary. (Mar.)