Natsu and friends visit the very first Wizard Guild to take a quest that no one has ever completed; 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; 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; Jellal finds out the secret of Touka.

Natsu and the others manage to drive away the Diabolos; Mercphobia starts to destroy Ermina and its people, forcing Natsu and his friends to make a tough decision; the White Mage sets out to do what she came to do.