I need help

Hi guys, i know its been a while but i need help finding a story.
The main 6 and spike are sent on and adventure to the desert to investigate a changeling spotting. discord is already there and with his magic drained because of the sand from the desert, he cant do much. Twilight steps on the sand and has some of her magic drained as well. the cross the desert to find a kingdom where there is a bad king ruling the kingdom. They also find out that there is a breeding farm for dragons to where spike gets taken there. This is set before season 4 and maybe even season 3. It is completed i think but that's all i know. Please help me find this story!!