In a sudden twist of fate, students from a high school are whisked away to a mysterious realm where they face monstrous threats and discover newfound superhuman abilities among them. Divided into the powerless Stay Home faction and the gifted Exploration faction, a dark betrayal unfolds as the Exploration members turn on their peers. Amidst the chaos, our protagonist, an ordinary student with no powers, narrowly escapes a brutal attack and finds himself on the brink of death in a secluded cave. As despair looms, a peculiar slime creature appears, consuming his injured hand. With his last breath, he pleads for salvation, whispering, '...please... someone, anyone... help me.'