A Forever Summer by Havelah McLat:
 
It’s hard to know who you can trust, when you can’t remember your past.

Katherine is an artist struggling with the grief of losing her mother at a young age. When her father dies, she and her sister unexpectedly inherit a house in Westchester Bay—a house she doesn’t remember.

When she finds a strange collection of old letters addressed to her, she starts to question everything. Her dreams and drawings all seem to hold a secret, a hint of who she was before the day her mother died.

While searching for answers, she befriends Janson Caswell: a kindhearted man with a complicated past of his own. The deeper their relationship grows, though, the more they are faced with a darker reality.

Will the truth tear them apart?