On the eve of the First World War, two friends go on a fishing holiday in Scotland before joining up. While staying at the house of retired General McLeod they become aware of mysterious apparitions on the loch. Matters turn more serious when Myra, the general's daughter is struck blind at the same place as the apparitions were seen. The two set out to investigate the cause of the strange events, and what role, if any, the rich American has in the affair, as they try to solve.. Mystery of the Green Ray