Natsu and friends visit the very first Wizard Guild to take a quest that no one has ever completed: the “100 Years Quest". Meanwhile, new recruits join Fairy Tail, but one of them is a little odder than usual…

The town of Ermina turns out to be a city for fish, where the whole town is submerged in water during high tide. The moment the party mentions Water God Dragon, the fish turn hostile.

Dragon Eaters are after Mercphobia to gain the power of Water God Dragon. Natsu and the others join in the battle to aid him, but the foes are strong. Meanwhile, Gajeel, Juvia, and Lily investigate Touka despite the protest from Levy.

Natsu, Wendy, and Erza are captured by the Diabolos, and Lucy sets out to go rescue them. On her way, she meets someone unexpected… Meanwhile, Jellal finds out the secret of Touka.

Natsu and the others manage to drive away the Diabolos for now. Then Mercphobia starts to destroy Ermina and its people, which forces Natsu and his friends to make a tough decision. Meanwhile, the White Mage sets out to do what she came to do…