Who is Jenny Colville from The Unlikely Spy and what is their importance?

Jenny lives in the same village as Sean and Mary Dogherty. Her father is an angry man, raising her on his own, and strikes her when he is drunk. Jenny often goes to Mary for comfort and stays at the Dogherty house when her father is especially difficult. Sometimes Jenny sleeps in a little cave near the seashore, and it is where she is staying one evening when she sees Sean preparing a series of bonfires on the beach. Jenny falls in love with Neumann, who she believes is an injured British soldier staying with the Dogherty family.