This is just the introduction to the story you will be reading. I assure you not to read this one first. It would be better to start at the beginning, with Salilah's Story. Promise is next and then Yin&Yang. It all ultimately leads up to this.

When the Humanbender reaches the age of 18, he or she can visit our world. The only way known was burnt by the Fire Nation during the time of the 100 year war. But with the help of a hidden map, Salilah found the book of Atlantis, the lost empire that separated the physical boundary between both of the worlds she called home.

Over the past 3 years, she had been through a great deal of obstacles, but this task wasn't so hard. It was only dangerous, and no one, not the Humanbender nor the Avatar, had ever made it to the other side.