The Creeping by Alexandra Sirowy

Romance, friendship, and dark, bone-chilling fear fill the pages of this "genuine and truly eerie" (RT Book Reviews) debut in the spirit of Miss Peregrine's Home for Peculiar Children.
Twelve years ago Stella and Jeanie vanished while picking strawberries. Stella returned minutes later, with no memory of what happened. Jeanie was never seen or heard from again.

Now Stella is seventeen, and she's over it. She's the lucky one who survived, and sure, the case is still cloaked in mystery-and it's her small town's ugly legacy-but Stella is focused on the coming summer. She's got a great best friend, a hookup with an irresistibly crooked smile, and two months of beach days stretching out before her.

Then along comes a corpse, a little girl who washes up in an ancient cemetery after a mudslide, and who has red hair just like Jeanie did. Suddenly memories of that haunting day begin to return, and when Stella discovers that other red-headed girls have gone missing as well, she begins to suspect that something sinister is at work.

And before the summer ends, Stella will learn the hard way that if you hunt for monsters, you will find them.