Grace Culver's sharp tongue, has garnered her with the nicknamed "The Wasp." A spirited disagreement with her canning magnate father, John Culver, results from Grace's refusal to marry Kane Putnam, her father's business partner, and she orders her new chauffeur, Tim Purcell, to take her and her maid Miller on a drive. On their return, they are captured by Brazsos, a German spy who plans to blow up her father's munitions factory. Grace learns of the hidden tunnel Brazsos has excavated to the factory, and as Miller escapes to alert the police, Grace unties the chauffeur and leads him to the tunnel. When the bomb explodes prematurely, Grace and Tim become trapped, and facing death, they confess their mutual love. The two are rescued, after which Grace discovers that Tim actually is wealthy Yale football star Harry Cortland, a revelation that delights her father.
