At the end of every week, the runners had to spend 1 hour in a specific phone box of their own choice, connected by video link to a central studio, while their Tracker attempted to find them live on air. The tracker was told which grid square on the map the runners were in. If the door of the phone box was opened by the tracker, the runners were eliminated; if not, even if the Tracker managed to see them but not open the door of the phone box, they won the prize for that week.