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 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…

When Mercphobia goes out of control and almost takes out Natsu, a hand shows up to save him. And it belongs to someone Natsu didn't expect: The Fire Dragon God and the son of Igneel, Ignia.

As a thank-you for saving Ermina, Mercphobia gives the group information on the rest of the Five Dragon Gods. And while they're in the town of Tekka, they encounter someone who looks exactly like Erza...

After Natsu and the others took down Yoko, they meet Suzaku, a Dragon Slayer of Diabolos, who has been summoned from Earthland to defeat Selene. Also known as Sword Saint, Suzaku is a formidable foe and Fairy Tail is helpless against him.