*CUT TO THE CHASE*
NOTE: This spoiler was submitted by Jason
The film begins with a young girl who lives in a house with her dad somewhere in Washington State. Her name is Katie Price, and she has Xeroderma Pigmentosum which is a disease that forces her to stay out of the sunlight cause sun rays can cause severe damage to her. There’s a group of kids outside of Katie’s house pointing at her windows saying she’s a vampire that never comes out. Next thing we see a young boy named Charlie skating by on his skateboard. The narrator (older Katie) talks about how she has such a crush on Charlie who she’s obviously never met. One of the young kids knocks on Katie’s door, and her father (Rob Riggle) says she can’t come out and play cause it’s daytime, but this girl whose name is Morgan demands to see her and says she’ll be back later. Morgan becomes Katie’s best friend.
Fast forward to present day and Katie (Bella Thorne) is graduating from high school, only she’s been homeschooled. Her dad gives her a present, and it’s a guitar from Katie’s mom who we find out died when Katie was very young. Katie begs her dad to let her go down to the local train station and play the guitar once the sun goes down. At night Katie can venture out and do anything like a normal person. As she’s playing the guitar at the train station Charlie (Patrick Schwarzenegger) sees her and is struck by her singing. He goes up to talk to her, and she freaks out with nerves and packs up her guitar and runs back home, accidentally leaving her journal behind. Charlie asks Morgan if she knows who Katie is and Morgan arranges for Katie to pick up her journal at the train station the next night from the station manager. Only instead Charlie is there with the journal to surprise her. She’s nervous again, but he convinces her to walk home and talk to him.
A few days later Katie texts Charlie inviting him to a party at Morgan’s co-worker's house. The party turns out to be super lame so Charlie being a cool kid invites them over to another party that is packed. Charlie is being hit on by another girl at the party, but it’s clear he likes Katie, and they dance, and eventually, he invites her to go for a walk where they share their first kiss on a boat that Charlie is tasked with keeping up for the summer. We then see them on a series of dates at night because while Katie has not told Charlie of her condition, she continually says “I’m busy during the days but can come out at night.”
Charlie takes Katie on a surprise train ride date, and they go to Seattle where they see a concert and walk around the city. Charlie makes Katie play a song at the pier, and a crowd gathers to watch her. They take the train back home and go swimming in the night water. While laying on the beach, Charlie says “get ready for the most beautiful sunrise.” Katie checks her watch and realizes that it’s broken from the water and that the sun is almost coming up. She freaks out and starts running home. Charlie eventually catches up to her in his truck and drives as she’s screaming for him to hurry. He pulls up to the house and as she’s running in the sun has risen and shines on her for a few seconds. Morgan and Katie’s dad arrive at the house at the same time, and Morgan tells a confused Charlie that Katie has XP.
Katie goes to a doctor and is told that her brain is contracting due to the sun exposure and she’s starting to get twitches. She refuses to take Charlie’s call, and he is shown researching XP. Charlie has a big swim meet to earn a scholarship during this time and is motivated by Katie telling him not to give up on his swimming. Charlie is invited over to the house by Katie’s dad, and they reconcile even though she tries to break up with him cause of her condition. Katie tells Charlie that she’s watched him outside her window for years and how she always loved him.
On another one of their dates, Charlie takes Katie to a recording studio where he’s hired musicians to help her record a song she wrote called “Charlie’s Song.” She records it even though she’s getting sicker and weaker. Charlie uploads the song on youtube. Soon after Charlie says he’s going to clean up the boat one last time before the owners get back and Katie begs her dad to let her go sailing around the harbor with Charlie, even tho the sunlight is out. It’s clear at this point she is dying, and this is her dying wish. They go sailing, and we see flashbacks of their romance. The next scene is Morgan, Charlie, and Katie’s dad spreading her ashes in the water where she used to play guitar with her mom. Charlie is then shown going to Berkeley for college and to swim when he hears “Charlie’s Song” playing on the radio. We’re told it has 2 million Youtube views. Charlie texts Katie’s dad who plays the song for his whole office. Charlie pulls over as the song is playing and reads a final letter Katie wrote him in her journal that she left for him, professing her gratitude and love for him.