Without A Trace

Lady Philippa, the wife of Sir Aymer - a knight of the realm - disappears while travelling from her husband's manor to Bampton. She and her maid are travelling in an enclosed wagon, whilst her husband and his grooms and a squire are mounted. When the party arrives at Bampton Castle neither the lady nor her maid are within the enclosed wagon: they have simply vanished.
As the disappearance may have happened while the travellers were on Lord Gilbert's lands, his surgeon and bailiff, Hugh de Singleton, is assigned to discover what has happened to the lady. Has she been taken? Her has she fled her husband?
A few days later her husband receives a ransom demand, and Hugh is named to deliver the money. Why him? The ransom is paid, but the lady is not returned. Can Hugh help find her, or is it already too late?