So we get some answers and important information in this chapter.
Most importantly, it turns out that Dmitri is innocent and that it really was Smerdyakov who killed Fyodor. Smerdyakov goes on to blame Ivan for the murder because of the ideas that he put into his head. Alyosha gets sent around as a messanger boy and come to find out that Lise is hysterical and upset. She ends up breaking the engagement and acts loopy as ever. And after Smerdyakov confesses to Ivan, he returns to his room and is confronted by a hallucination - a woman who claims to be the devil. He starts to have a mental breakdown when Alyosha arrives to bring him the news that Smerdyakov had hung himself.