From back cover: > Penny is looking forward to a lengthy > visit from her son, Dr. Alex Spring, > when she receives a summons from > Scotland Yard. Where is Sir Tobias > Glendower? It happens that a young > Russian ballerina is being held in > custody as primary suspect in the > bizarre bludgeoning-to-death of one of > the members of a visiting Soviet > *corps de ballet*. But she will speak *only* to Sir Toby, who she claims is her father! Toby is eventually reached > at his private archeological > excavation deep in the Welsh > countryside - the "folly" of the title > - and plunged headlong into mayhem and danger.