Winter's Mermaid (Mermaid Seriess)

By uncovering a veritable fountain of youth a doctor comes to learn the extraordinary price of immortality. Despite solving the riddle to everlasting life, she watches in horror as the human race nearly goes extinct overnight. The few survivors, a motley band of misfits, are now bound in servitude to an older and superior race if they wish to continue living. Those who were once deadly enemies become trusted allies while friends and lovers turn upon one another. As the old world fades away a new one rises, one in which death has no meaning, where institutions such as marriage and fidelity vanish, a place where murder and mayhem become acceptable behavior, and betrayal is the norm. To what lengths would you go to stay forever young?