The show "13 Reasons Why" is about a high school student named Hannah Baker who commits suicide. Before her death, she records a set of thirteen cassette tapes that explain the reasons why she decided to end her life. Each tape details the people and experiences that contributed to her mental health struggles, including bullying, peer pressure, and sexual assault. The story follows a classmate, Clay Jensen, who listens to the tapes after Hannah's death and learns about the impact of these events on her decision, as well as the broader social issues faced by modern youth. The series explores themes of mental health, trauma, and the consequences of actions on others.