Avatar: a true master

This is the summery of book 1. You can read it and decide if it's worth your time to read the whole 12 chapters or not After 17 years, the new avatar finally shows up: an earthbender named Yin. He already mastered earthbending because he trained for the past 11 years with his sensei ushi On my page I have an explanation as to why Yin is the avatar and why, as known, the cycle didn't end with Korra (Everything about ushi will be revealed in book II: Spirits) but he still has things to learn. When he showed up, he found out that 80% of the fire nation is disappearing, a guy named Zei and his troupes are drowning most of it and are planning on something else after. What Yin and his friends know is that they need to stop them before the blood moon comes or they won't be able to stop them anymore but no one knows what happens when the blood moon shows up. Unfortunately, they fail and Yin's only hope are 4 guardians. The guardians' stories and faces will be discovered at the end of chapter 10 (I don't want to say a lot in the summery) and so is the way that Yin, the avatar, can connect with them  How will they help him and what will happen in the way?  (By the way, the chapters that I like the most are 5,8 and the rest after 8)