For the past two years, Amie Teller has been stuck in a time loop. Each day, she wakes up, and it's September 17. Same day, same weather, same people, same conversations. Until one day, it's September 18, and Amie is free. Before she can celebrate, Amie learns her neighbor was murdered the day before--the day Amie has lived hundreds of times. Amie knows she has to help; nobody knows yesterday like she does. But acclimating to her new nonrepeating life proves to be more difficult than expected. How does one resume their life after a time loop, anyway? Assisted by an ex-girlfriend who wants to make their friendship work and a grumpy neighbor who spends his days building Rube Goldberg machines, Amie sets out to track down who killed (and killed and killed and killed) Savannah Harlow.