The Drowning Summer — Christine Lynn Herman

In this contemporary fantasy by the New York Times bestselling author of All of Us Villains, two girls find themselves drawn to each other while using their supernatural powers to solve a crime -- until things take a deadly turn.

Six years ago, three Long Island teenagers were murdered -- their drowned bodies discovered with sand dollars placed over their eyes. The mystery of the drowning summer was never solved, but as far as the town's concerned, Evelyn Mackenzie's father did it. His charges were dropped only because Evelyn summoned a ghost to clear his name. She swore never to call a spirit again.

She lied.
 
For generations, Mina Zanetti's family has used the ocean's power to guide the dead to their final resting place. But as sea levels rise, the ghosts grow more dangerous, and Mina has been shut out of the family business. When her former friend Evelyn performs another summoning that goes horribly wrong, the two girls must uncover who was really behind the drowning summer murders -- and navigate their growing attraction -- before the line between life and death dissolves for good.
 
Beautifully written and enticingly witchy, The Drowning Summer is an eerie story perfect for reading under a full moon.