Morris Bober is a Russian Jew who emigrated from Russia to New York when he was just a teenager. He and his wife, Ida run a grocery store in Brooklyn, but a new store is undercutting their prices and driving them out of business, so the family also depends on Helen, their daughter, to help out monetarily. She works as a secretary. This difficult situation is made even worse when two thugs knock Morris unconscious and rob his store.
In the aftermath, Morris meets Frank Alpine, a poor man in desperate need of work. Frank begs Morris for even an unpaid position at the store, but Morris sends him away. The two reunite when Morris finds him living in the cellar. Frank admits that he is responsible for the missing wares, but even though he has stolen from Morris, he only took what he needed to survive. When Morris trips and knocks himself unconscious, Frank steps in and starts working without permission. Frank's work in the store leads the store to thrive, and Morris wants to pay Frank for his outstanding work, but secretly, Frank is one of the thugs who jumped him before, and he has been stealing a salary from the store without Morris knowing.
When Frank meets Helen Bober, he is drawn to her personality, since she also doesn't play by the rules. Helen finds out the hard way that her first lover, Nat, didn't love him, so when Frank pursues her, she makes him wait until she's sure the two are really in love. Her name also corresponds to the femme fatale of Helen of Troy.
Frank's situation worsens when Morris discovers him taking money from the register, and even though Frank has been actively trying to repay what he has stolen, Morris makes him leave. Helen agrees to meet Frank in the park, excited to tell him that she'll agree to have sex with him, but instead a drunk nearly rapes her. Frank arrives just in time to stop the man, but instead of hearing Helen's confession of love, he just finishes the job himself by forcibly raping her.
Morris can't catch a break. The store across the street has reopened, and in another clumsy mistake, he accidentally leaves his radiator unlit, nearly suffocating himself to death in his sleep with the gas fumes. Frank continually tries to involve himself, and although he eventually saves the day (often, in fact), Morris continually rejects him. Morris finally decides to burn the store down for the insurance money, but his clumsiness leads him to almost die in his own fire.
Then, in a twist of fate, the Karp store is burned down. They use that insurance money to buy Morris's store from him. Overjoyed, Morris goes out into the snow to clear a path for customers, but instead he catches pneumonia and dies three days later. He accidentally forgot to wear a coat.
In Morris's wake, Frank takes over and commits himself to providing Helen with the education she wants so badly. She is warming up to him again, because in his new role, Frank has adopted Morris's moralism and identity. He even goes so far as to have himself circumcised, and after Passover, he converts to Judaism.
