Jeremy has dreamed of diving the Big 5 dungeons since one of them killed his father fifteen years ago. When a moment of misplaced heroism costs him his diving license before he can even start, he ends up partnered with the girl he tried to help and a bookworm brunette who joins them along the way. Together they enter dungeons on their own terms, and Jeremy's unusual abilities — which dramatically enhance the team's odds — draw the notice of powerful people who want those abilities for themselves.

Jeremy is confident, instinctively protective, and driven by grief-fueled purpose. He is not the most nuanced protagonist in the genre but he is reliably likeable — a straightforward hero whose growth is less internal than tactical, learning to lead a team of capable women who each have their own skills and personalities. The harem dynamic is present but treated as earned through relationship rather than power.

Across six books Jeremy's team conquers all five dungeons of the Path of Progression, defeats a treacherous former mentor, and then takes on the Champion's League in far-off lands. Romance threads develop alongside dungeon victories, the team grows and evolves, and a final confrontation with a Dungeon Master threatening worldwide catastrophe demands everything Jeremy has built and everything he is willing to sacrifice. The series is a steady escalation from local dungeon heroics to world-saving stakes.