It has been 50 years since dungeons appeared on Earth. In the present day, exploring and streaming dungeons has become commonplace. Kuga became an explorer with his best friends, but was expelled from the party because he was a jack-of-all-trades hero. In despair, Kuga is thrown into the hidden boss room, which is rumored to be impossible to return from alive. A beautiful vampire named Alicia appears there. He prepares himself for death, but Alicia seems to be very interested in human streamers―― "Can you teach me Haishin...?" With nowhere to go, Kuga reluctantly accepts the proposal and begins an unprecedented stream hunting explorers. For some reason, the two's stream goes viral at an abnormal rate, and an unknown power awakens in Kuga...? Meanwhile, the party members who expelled Kuga are acting strangely as well... The strongest streaming heroic tale brought to you by this mismatched duo!