Continuing his adventure to get stronger in order to traverse deeper into the "Dungeon," Bell Cranel wanders the Orario city streets with his friends and the goddess Hestia. That evening, the city is filled with stalls and games as it celebrates the Holy Moon Festival.

Hermes, a god, hosts one such activity where participants are asked to pull a spear embedded in a crystal boulder; those who succeed will receive a special gift: a trip around the world and a divine blessing from the gods! Bell and his merry group challenge one another to claim the prize. But behind the facade of an innocent party game lies a preface for a daring quest ahead.

The anime's story will start where the third season left off, at the competition for who will open the Triple S international sporting event. Raging Entertainment's HE★VENS idol group had hijacked the competition between QUARTET NIGHT and ST☆RISH, causing chaos. However, after the QUARTET NIGHT members suggest a certain idea, the three groups aim toward a new stage, with HE★VENS swearing to get their revenge on the other two groups.

Friends will only let you down—that is the sad truth Mei Tachibana lives with, ever since she was wrongfully blamed for the death of a class pet by her so-called friends in grade school. Since then, she stays away from people in order to avoid ever being hurt again. However, Mei's life begins to change drastically when a misunderstanding in high school causes her to encounter popular student Yamato Kurosawa. Yamato finds her intriguing and insists on being her friend, even though Mei wants nothing to do with him. But when a dangerous situation ends with Yamato kissing Mei to save her from the unwanted attention of a stalker, Mei begins to develop feelings for him. On the heels of her discovery that their feelings are mutual, they start dating and she gains not only a boyfriend, but friends as well. Mei, however, finds it very hard to adapt to this new lifestyle, especially in expressing her true feelings towards Yamato. Throughout misunderstandings of their new relationship, each other, and the attentions of other girls, Mei and Yamato slowly grow closer and learn the true meaning of those three little words: "I love you."

The story is set in Aquafall, a fantasy world abound with water and greenery, and populated by dragons and fairies. Meteorites suddenly bring forth evil creatures that threaten all living things on the planet. The fairy Syrup assembles the Aquafall Defense Force, with three girls of the dragon clans as recruits. The story follows Syrup and the dragon girls Leviathan, Bahamut, and Jörmungandr as they work together to battle enemies and grow up.