Moon Rains is a teenager, who cannot shake off a terrible cold. Trying to avoid traditional doctors, her mother drags her from Oxford to the most remote parts of the Shetland Islands, to attend an interview at a world-famous Clearlake Institute, whose innovative approach to health promises to cure Moon’s pesky illness. The Clearlake Institute is run by a jolly Dr Larsen. But it soon becomes clear that it is neither world-renowned nor provides anything in terms of the innovative approach. Gnarly old witches roam the hallways at night, the clocks do not work (except for when they spin round and round at odd hours). And worst of all, children seem to disappear after they are summoned into the mysterious room 217. It is up to Moon and her new friends to uncover the dark secret of the Clearlake Institute before it is too late.