The Return by Katie Winters

Elise has abandoned Los Angeles for the trip of a lifetime. With her mother’s diary and memories in tow, Elise dives into the secrets of Mackinac Island armed with a single name – Tom – to discover the identity of her father.
Mackinac Island is far more beautiful than she’d expected. She’s a California girl through-and-through, but she finds herself captivated with the turquoise waters, the gorgeous rocks, and the carriages, which make her feel as though she’s fallen back in time.
Despite the daydream of it all, Elise soon finds herself in the midst of a nightmare.
Not everyone wants her to find her father.
In fact, some people will do anything to get her off the island for good.