After five years of being ridiculed and treated as a mere handyman by his A-rank party, Thunder Pike, the red mage Yuke Feldio finally reaches his limit and walks away. His former companions, who failed to recognize the true value of his support magic and extensive preparations, quickly find themselves struggling without him. While searching for a new group to join, Yuke unexpectedly encounters three of his former students: Marina, Silk, and Rain. The trio, who hold their teacher in high regard, welcome him into their low-ranking party called Clover.

Set in a fantasy world where adventurers explore dangerous, multi-layered dungeons for treasure and glory, the story follows Yuke as he rediscovers his purpose. Using his versatile magic, alchemical knowledge, and strategic mind, he elevates Clover from novices to a formidable team. Their successful quests, often broadcast live by a magical artifact, quickly bring them fame and rapid rank advancement. As Clover climbs the ranks, their dream becomes conquering the world's most challenging dungeon, known as Achromatic Darkness. Meanwhile, the disgraced Thunder Pike party, led by the bitter Simon, begins to unravel and plots revenge against Yuke for leaving them.

The narrative arcs escalate from personal rivalries to world-threatening chaos. Early episodes focus on Clover's formation and Yuke's mentorship, contrasting their effective teamwork with Thunder Pike's dysfunction. A major arc sees Thunder Pike, backed by a corrupt noble, ambush Clover in a dungeon, leading to a brutal confrontation where Yuke's former party members meet grisly ends and Simon is transformed into an undead immortal. Later, as Clover delves into the Achromatic Darkness, Yuke is revealed to be a prophesied hero destined to seal a catastrophic Abyss Gate. The party becomes entangled in political intrigue, including a plot to force Rain into a political marriage, which Yuke averts by forming marital bonds with all the female members to protect their unity. By the end of the first season, Clover has solidified its status, Yuke has accepted his heroic role, and the group sets its sights on even greater perils threatening the entire world.