In a society where Monster Crests dictate one's social status from birth, the narrative follows Rayn, a young boy enrolled in a prestigious academy for elite Monster Trainers skilled in taming and battling monsters. Despite facing ridicule for his choice of training lowly slime creatures, Rayn remains unfazed, finding joy in bonding with his loyal slime companion, Pem Pem. Standing in stark contrast is Ellenia, a formidable dragon trainer admired for her beauty and strength. Ellenia holds a mysterious fascination with Rayn, believing him to be intertwined with her own fate.