悬念

An isolated house in deserted area is too remote for a servant, who leaves a note, quietly exits the back door, and puts the key under the mat. Alone in the house is a mother and her infant. A tramp watches the servant leave, then begins to skulk. The woman sees him outside as he discovers the latchkey. She phones her husband, who's working in town, and he jumps into a car idling in front of his office. He races toward home while the car's owner (and the police) are in pursuit. The tramp grabs a knife and heads up the stairs toward the defenseless woman. Can the husband elude the police long enough to rescue her or will the tramp have his way?