The Key of the Starry Sky arc is an anime-exclusive story arc of the Fairy Tail series. The arc happens between the X791 arc and the Grand Magic Games arc. When Lucy's cousin, Michelle, arrives at the Fairy Tail Guild to give Lucy a memento left to her by her father, Lucy and her friends go on a quest to unveil the mysteries surrounding an ancient device sealed away for centuries, the Infinity Clock. However, with the involvement of the Legion Corps and the newly restored Dark Guild, the Reborn Oración Seis, the fate of the world as it is known is left to none other than Fairy Tail to protect.