Ghost Chamber by Celia Rees
The Goodman children are spending their first proper holiday with their estranged archaeologist father since their parents divorced - looking forward to seeing what his new house in the country is like. They know it's a crumbling old pub, which he is renovating, but not long after they arrive, they realise their dad bought the pub for a reason, because of what is said to be buried beneath it. Objects move in the knight, strange noises can be heard coming from the cellar, and a creepy looking guy is hanging around the village asking sinister questions about their dad, and the old pub....13 year old Hugh Goodman is intrigued, and digs a little deeper into the mysteries of the house than he should. Before he knows it he and his siblings are caught up in a horrifying secret, and the discovery of an ancient chamber, where lies the restless ghost of a buried templar knight. Will the ghost avenge his own death using innocent children, or can they manage to beat evil forces?