Nikiri Dungeon's story starts 104 after the events of Tales of Phantasia. The story starts out about a fair that slowly loses it's power because it cannot locate it's friends. eventually the fairy etos runs into a women by the name of norm who heals her, though this comes with a price. Etos is then tasked by Norm to raise and take care of two infants. Grateful she does just that. 13 years past and tragedy strikes the once infants dio and mell's hometown of Valhalla as such they must work togethor to collect the summon spirits of the world and stop the evil force.
Nikiri Dungeon handles traversal quite similar to past tales though there is no overworld. It is instead replaced with a view of the area and the player can click and choosse the locations they would like to visit.