One year after her beloved sister drowned while swimming in cold New England waters, sixteen-year-old Brandi Vine is still struggling to understand what happened. As she mourns on the rocky beach where her sister's lifeless body washed ashore, she is unaware that a pair of haunting gray eyes is watching her from beneath rolling ocean waves.When Brandi attends a party that goes horribly awry, the mysterious owner of the gray eyes emerges from the ocean depths and comes to her rescue. She only sees him for a few brief moments, but that's all it takes to turn Brandi's world upside down. What were the strange markings on his neck that seemed to flutter with every breath? How did he possess such inhuman strength and grace? And why did he look at Brandi with such longing?Brandi's fascination with the Swimmer grows. She makes it her mission to find him again and learn who - and what - he is. Meanwhile, the Swimmer's fascination with Brandi compels him to leave the safety of the ocean behind, to be with her at all costs. They are from two different worlds, but neither of the star-crossed romantics can resist the pull of the other.Ultimately, when her feelings for the Swimmer swell beyond her control, Brandi comes to realize that the strange young man from the sea can unlock the secret of her sister's final swim.