Even If You're In the Deepest Darkness, I'll Be Your Light

Hikari washed ashore on the islands at the age of 6, along with another girl named Kairi. Kairi is adopted by the mayor while Hikari is taken in by Riku's family. Over the next several years, she becomes close with Sora, Riku and Kairi. After the islands are destroyed and the 4 are scattered, Hikari must face many trials to help her friends. During this journey she will discover who she is. But what will be the price?