A self-centered college student wakes up on her birthday in the dorm room of a classmate she doesn't remember much about. As the day unfolds, she navigates through the typical experiences of a college student: dealing with a hangover, enduring a surprise party, and navigating various social circles. In spite of the festivities, she is continually harassed by an unknown assailant in a baby-face mask. The day takes a dark turn when this masked figure brutally murders her. However, instead of succumbing to death, she wakes up again in the same classmate's bed, forced to relive her birthday in a looping sequence.

With each repeat of the day, the student becomes increasingly aware of the details surrounding her untimely death, prompting her to investigate the identity of her murderer while trying to break the cycle. As she experiences the same events, she gains insights into her own life and the lives of those around her, changing her approach to the people she meets, and the choices she makes. With time running out, she struggles to uncover the truth, hoping to stop the loop and prevent her death before it is too late.