Bulldog Drummond at Bay

This is the ninth Bulldog Drummond novel. Hugh Drummond is staying in an old cottage. He is alerted by the sound of men shouting, followed by a large stone crashing through the window. When he goes outside to investigate, he discovers a patch of blood on the road and is interrogated by two men, Emil, and his companion. They inform him that they are chasing a lunatic who has escaped from a private asylum. The men bribe him and also demand he keeps his mouth shut. Drummond plays dumb, but when he discovers a cryptic message with the content "Mary Jane. Urgent. G G Pont. A5", he decides to investigate the mystery.