A team discovers clues to Scotland's first kingdoms, metal detectorists unearth a hoard of Viking treasure, and a new housing development reveals a graveyard of Iron Age warriors.

A team unearths a mass grave, divers search the Thames for clues to a 17th-century tragedy, and a metal detectorist makes the find of a lifetime.

This episode visits sites in the west of Britain, including one uncovering the rituals of Stonehenge.