Alex lives a comfortable life with his wife Beth in the leafy suburb of Silver Vale. Fine, so he's not the most sociable guy on the street, he prefers to keep himself to himself, but he's a good husband and an easy-going neighbour. That is, until Beth announces the creation of a nature trail on a local site that's been disused for decades and suddenly Alex is a changed man. Now he's always watching. Questioning. Struggling to hide his dread. As the landscapers get to work, a secret threatens to surface from years ago, back in Alex's twenties when he got entangled with a seductive young woman called Marina, who threw both their lives into turmoil.