A Secret Inheritance. B. L. Farjeon

Gabriel Carew is a young boy living with his parents in poverty, when one day his father receives a latter that changes their lives. Their distant relative has died and left his fortune to Gabriel's father. When he grew up, Gabriel decided to use this fortune to travel around the world. At one of his travels, in Gascony, Gabriel had an accident and his life was saved by a certain German doctor called Louis. As he was recovering in doctor's house, Dr Louis received one letter that made the wheel of suspicion spinning for Gabriel. Doctor tells him a story of two brothers who became bitter enemies because of a certain secret inheritance and Gabriel becomes determined to resolve its mystery.