With the Golden Age of Narnia long gone, Narnians hide in the forests, rivers, and caves from the invading Telmarines. One Narnian, the only and last of her kind, half mer and half Daughter of Eve is set on a path that can shake the very foundations of what the country has known for generations. Heidi Shallows joins the young Prince Caspian in his rising efforts to free Narnia with the support of the kings and queens of old. But love makes things messy in war and a tail is useless in battle. Heidi must keep both her sword and her witts sharp, otherwise, it's anyone's guess to what might happen.