Coincidence leads workers to unmarked grave at a construction site.
As the earthmover lifts its bite of earth, a skull rolls free. Police gather the bones and pathologist Amos Atherton fits them together into a human jigsaw puzzle. Amos pieces together a teenage girl. As Thackery informs his boss about the unusual situation, his boss just happens to remember clearly the unsolved disappearance of an Italian girl, Mariella Bonnetti, on Coronation Day in 1953. Grandmother vividly remembers the adults and children on Peter Street where they all lived in 1953, in Bradfield, near Yorkshire, England.