What if all the crushes you ever had found out how you felt about them… all at once?

Sixteen-year-old Lara Jean Covey keeps her love letters in a hatbox her mother gave her. They aren’t love letters that anyone else wrote for her; these are ones she’s written. One for every boy she’s ever loved—five in all. When she writes, she pours out her heart and soul and says all the things she would never say in real life, because her letters are for her eyes only. Until the day that her sister Kathrine, secretly mailed the letters and Lara Jean’s love life goes from imaginary to out of control.