The Haisuna Desert is the desert where Leon and Leona, the two main characters, enter a tournament for entry into Mount Rakken. Here is a summary of what happens. Rugar the Grand is scolding a woman for selling water at high prices. You interfere and he challenges you. After you beat him, you find someone and then notify him you are entering the tournament. He challenges you to test your skills. After entering the tournament, Rugar the Grand is defeated in the first round. You go through many battles. When resting for the final fight, a woman comes in and tries to bribe you. She offers you gold in exchange for losing on purpose. After you reject the offer, she orders suspicious men to attack you. After this, you battle in the finals. When you win you are sent to go into Mount Rakken, where you meet a beserk First One called Vulcarex. After this, you recieve special gems and return a hero. Then, you go to the winter regions.
Sorry for the lack of detail, for I have been past this part already and do not remember everything.