When David, Peter, Mary, Dickie and Tom of the Lone Pine Club go on holiday together, they know something exciting is bound to happen. They soon find themselves investigating a sheep-stealing plot and following a trail which leads to the strange house with grey walls.

The Secret of Grey Walls 2007, Girls Gone By, Bath

ISBN-13: 9781847450265

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Secret of Grey Walls 1995, Scholastic Hippo, London

ISBN-13: 9780590559195

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The Secret of Grey Walls 1983, John Goodchild Publishers, Northamptonshire

ISBN-13: 9780903445887

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Secret of Grey Walls 1975, HarperCollins Distribution Services

ISBN-13: 9780006910459

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