Mark (Kyle Allen) is a senior in high school who lives in a small town, but he realized quite a while ago that he's living the same day over and over again. He tries to find small ways to amuse himself, such as helping people about to have minor accidents or incidents, such as a girl who gets hit in the head by a beach ball at a pool. He tries to find all the amazing things that happen each day and draws a map of what happens in each area of town and at what time.
When a girl named Margaret (Kathryn Newton) intercepts the beach ball one day and then keeps going without explanation, he follows her and finds out she's also aware of the time loop. Together the two teens explore all the things they wanted to do in their small town—with little consequence to their actions. As feelings begin to develop between the two, Mark tries to come up with solutions to get them out of the time loop—but he's surprised to find Margaret isn't in a hurry to move forward. There's something holding her back in this one day, and when he finds out what it is, he begins to understand why.