The Mer: Part IV: Beginnings by M. Culler

The fourth part in The Mer series by M. Culler.
She took a new form. She took a new name. She's ready to begin a new life with the Mer. Now known as Val, our reluctant heroine is determined that she'll be brave as she faces challenges in an ancient world that is brand new to her. The world of the Mer is one that is confusing and sometimes frightening, one that seems familiar, but holds strange secrets and rules. The hardest challenge? Knowing she must never have contact with the family she left behind. Fate is ready to test Val's obedience to the first and most important rule of the Mer, avoid contact with mortals. Disobeying the rule would mean certain banishment from the clan.
What is the true meaning of bravery? To risk everything for someone you love? To survive alone without the Water's protection or the clan's help? As Val begins her life with the Mer, she must make a harder choice than she could have imagined.