The Grange at High Force
Philip Turner
 The novel opens in All Saints' church in Darnley Mills. Some time ago, Peter constructed a Roman ballista and accidentally broke a window in the church while testing it. Two pigeons, taking advantage of the broken window, built a nest in the nave. "Operation Bird's Nest" is now underway, with Arthur climbing up to remove the nest. The gathered crowd below are (quite unnecessarily) concerned for his safety, except for Miss Cadell-Twitten, who is still seething about the ejection of the birds from the church. Arthur poses in an empty niche, which Mr Pritchard explains once held a statue of the Virgin Mary. The same day, the three friends set off to explore High Force on the moors, to see the waterfall and the tiny abandoned church of Little St. Mary's. Peter has an accident with his bicycle, aptly named the Yellow Peril. Seeking help at the Grange, they meet the Admiral and Guns, and are fascinated by the ancient ship's cannon on the Grange terrace and the workshop in the cellar where a mill wheel is being constructed to provide reliable electricity. The Admiral is in turn interested to hear about the ballista, and proposes that both weapons should be fired at targets to test their accuracy. They all go together to look at the church, and find it has been invaded by dozens of birds. It needs re-roofing, and thorough cleaning. They set about the various tasks with energy and enthusiasm, also stumbling on a mystery concerning the statue. Miss Cadell-Twitten hints that she knows the answer, but refuses to tell them because they accidentally frightened her bird Augustus. Plans to fire the cannon are scotched by the police sergeant, until an opportunity arrives just before Christmas, when they succeed in sinking a makeshift raft. Immediately afterwards, a blizzard starts and they help Mr Ramsgill gather in his scattered flock. A exceptionally heavy snowfall cuts off the moor, and even with a snow plough it is a struggle to return to the Grange through the deep drifts. David, the only one who can manage the snowshoes, checks on Bird Cottage and finds Miss Cadell-Twitten suffering from exposure. Grateful for her rescue, she tells them where to find the statue, which is recovered and returned to All Saints. The novel ends with a two-gun salute, as the Admiral and Guns set off in the spring in their new boat to explore the coastline of the British Isles.