The Manor House School by Angela Brazil.
THE Old Manor is a delightful house in Somerset, to which the lucky girls are transferred with the rest of the school, while alterations are carried out in the less romantic buildings to which they have grown accustomed. The Manor has its own mystery, which Lindsay and Cicely are determined to solve, partly from curiosity and partly for the sake of Monica, who is really its owner.
The thrill and amusements, together with their investigations, bring success and a thrilling climax to this fascinating story.