While in pursuit of two bandits with his master, Patrolman Robert Conway, Peter the Great tears away the coat sleeve of Jimmie Bryson, a young bank employee. Jimmie's sister Mildred notices the torn sleeve, and his shady friend Al Stokes makes advances to her. Stokes forces Jimmie to give him the combination of the bank safe, which he plans to rob that night. Meanwhile, Bob, having taken an interest in Mildred, is introduced to Jimmie and becomes suspicious when Peter snarls at the boy, but he declines to arrest him at the pleas of Mildred. Stokes, who is proven to be Peter's former owner, claims the dog and leaves. When Jimmie refuses to go through with the robbery, he is tied up by the crooks, who abduct Mildred; however, Peter frees Jimmie. Bob is trapped by the bandits in the bank, but Jim frees him; and following a thrilling automobile chase, Stokes is killed.—AFI