Sisters of Salt and Iron (Sisters of Blood and Spirit Series, Book 2)

Lark Noble is happy. She finally has friends people who know she can see and speak to ghosts and still care about her and she has Ben, the cute guy she never saw coming. Wren Noble is lonely. Unable to interact with the living, she wants to be happy for her sister's newfound happiness, but she feels like she's losing her. It doesn't help that Kevin, the very not-dead guy she was starting to fall for, seems to be moving on.