In 1976 San Francisco, a creative and intelligent fifteen-year-old girl named Minnie begins recording an audio diary to document her thoughts and experiences as she embarks on a journey of sexual discovery. Living with her permissive single mother Charlotte and younger sister, Minnie feels both neglected and free to explore her burgeoning desires. One day, she starts an illicit affair with her mother's boyfriend, Monroe, which triggers a cascade of complex emotions and challenges. As she delves deeper into this relationship, Minnie grapples with the thrill of newfound intimacy and the guilt of betraying her mother.

Minnie pours her heart into her art, dreaming of becoming a comic book artist while trying to understand her identity and place in the world. Her friendship with her best friend Kimmie and her interactions with various others contribute to her self-discovery. Throughout this formative period, Minnie's diary captures her raw, unfiltered reflections and growing pains, highlighting the turbulence of adolescence and the quest for self-acceptance. The narrative unfolds with a mix of candor and introspection as Minnie navigates the intersection of innocence and maturity.