Five on Finniston Farm

On holiday at Finniston Farm the Five meet Harry and Harriet, who are identical twins, and join forces with them against some unpleasant American visitors-Junior and his father. Finniston Castle, which was burned down many years ago, interests both parties; especially the dungeons and what is rumoured to be hidden inside them. After a lot of hard digging, the Five find a secret passage which leads towards the dungeons...