Isla Monroe has had a crush on her dad’s best friend, Ethan Hayes, for as long as she knew what the word crush meant. It had been at least 4 years since she had seen Ethan, she thought she had grown out of it, because after all crushes are fleeting. Then he shows up at her father’s birthday party looking so devastatingly handsome and suddenly once again she’s eighteen and making the same mistakes all over again. Only this time they aren't just mistakes. Caught between what everyone expects and what was supposed to be a one night fling, Ethan and Isla find themselves falling harder than any of them intended. But when obsession becomes dangerous and someone from Isla's past refuses to let her go, they'll discover that crossing the line was just the easy part.