A local historical mystery is solved by a carefully balanced quartet of British schoolchildren doing a classroom project. This has the makings of a mildly didactic but pleasant enough story from this venerable author of 98 books (Bows Against the Barons, 1934): the caves beneath Nottingham do exist; the alabaster-carvers are a historical fact; a spectacular find of artifacts hidden long ago from Protestant vandals is plausible. A subplot about saving a fine old building from the greed of modern developers adds interest. Unfortunately, though, the characters here are merely composites of stereotypical qualities. The white boy (Rodney) is the natural leader and has the creative ideas; the black girl (Debby), who is not a good student but is a fine gymnast, comforts herself with hymns when she's in danger. When the fathers come to help with excavation, ""Rodney's father brought his tools. Debby's father brought only a pair of immensely powerful arms and a cheerful grin that shone like a moon."" Any one of these details might be acceptable, but the book is riddled with them--and not exceptional enough otherwise to warrant purchase.