One day, darkness enshrouded the world. Dungeons we see in games, books, and stories materialized out of nowhere. Dragons, demons, monsters, and all kinds of creatures burst forth out of the dungeons, terrorizing the world and causing chaos and destruction. But what comes after despair is hope, and the hope that humans needed came in the form of gifts. Powerful gifts that can clash with powerful dragons, banish the cruelest demons, and slay numerous monsters. Wielded by Earth's wonderful creations to defend its homeland. On the night of the apocalypse, Sei also received a gift. A peculiar gift that summons random things every day. On good days she summons a gun. On regular days a knife, and on her worst days, she summons a paper. "What the ****?! How the hell can this piece of ***** kill a monster?!" Yet this strange gift saved her and her friend's life that day. And will save many more in the future.To protect the few precious people around her, Sei struggles to survive in the apocalyptic world with her gift. To become stronger, she ventures out to explore the unknown world, gradually discovering the secrets behind the invasion of her world.