As the bank watch is inspecting the cellar vaults, where the gold supply of the bank is kept, he suddenly hears the sound of steady strokes on one of the walls. At first he will not believe this to be true, but be soon understands that somebody is trying to reach the gold supply. The bank director is immediately sent for, and at once appearing, he soon ascertains that danger is imminent. In order to keep the case quiet, he does not inform the police, but seeks the assistance of the famous detective, Pat Corner, who promises to take the case in charge. A design of the bank and the nearest surroundings shows quickly to the acute detective that a subterranean passage to the bank must originate from a public house in the neighborhood. He at once sets to work to examine this public house, and in an old barn adjoining the bank he finds the entrance to a subterranean passage. The landlord tells him that an old blind beggar by the name of Teddy sometimes is allowed to take refuge in the barn during the night, and Pat Corner's next thing to do is now to find Teddy, who lives in an old, decayed house in the city. Teddy plays his part as blind man and cripple so well that the detective leaves him, quite bewildered, not knowing what to think, but when he comes back, one moment later, Teddy has disappeared. As Pat Corner cannot find the secret entrance to the fox's den, he fetches his assistant and tells him to keep watch, while he himself examines the surrounding yards, trying to find another entrance. When he comes back his assistant has also disappeared. After a close examination Pat Corner finds at last a place in the wall where he thinks the secret entrance might be found. He quickly fetches three policemen and they have the wall blown up with dynamite. Pat Corner is just in time to save his assistant from a terrible death and to arrest Teddy and his accomplice, thus preventing them from doing further mischief.