Ihe two plot lines of Tom Robinson and Boo Radley are connected by the significant title: "To Kill a Mockingbird." For, the mockingbird motif unites Boo Radley and Tom Robinson as they are both harmless members of the society, but persecuted because of the townspeople's bias.
When Atticus tells his children that "it is a sin to kill a mockingbird," he means that it is wrong to punish innocent creatures. Like the mockingbird, neither Boo nor Tom does anything to harm anyone. And so, the climax of these characters' plot lines comes at the point at which they are endangered. For Tom Robinson, it is his unjustified trial for which he is tried for the crime of rape that he did not commit. But, because of the taboos and prejudices of his community, he, the innocent man, the mockingbird, is found guilty. For Boo Radley, it is his killing of Tom Ewell in order to protect Jem and Scout. Sheriff Tate should take Boo to the police station for a statement; however, he decides that this mockingbird, this innocent man, must be saved. Thus, the resolutions of these two plot lines differs, for the first "mockingbird," Tom Robinson, dies while the other "mockingbird," Boo Radley, is spared condemnation.