On an ordinary day in Tokyo, Satoru Mikami's life takes a drastic turn when a sudden attack leaves him on the brink of death. As he laments his unfulfilled life, a strange voice transports him to a mysterious cave where he is reborn as a slime creature with the power to assimilate other beings. In this new form, now known as Rimuru Tempest, he encounters a sealed dragon, Veldora, and forms an unlikely friendship. Determined to break Veldora free, Rimuru embarks on a journey filled with newfound abilities and a chance to rewrite his own story in a world brimming with adventure and uncertainty.