The Spy Who Came Out of the Bushes

This is the 20th novel in the Pitkirtly Mysteries series.
Maisie Sue's wedding is disrupted by shadows from the past, while Christopher fights against the inexorable intrusion of the future into his working life, and once again Amaryllis is not the only spy in town.
Danger lurks both in the depths of the nearby forest and in Maisie Sue's own home, where visitors do not always stop to admire the curtains.