Sung-joon, who was born with a different body from the others, was abandoned by his parents and sent to a ‘facility’. During the day, he was given strange medicines to modify his body, and at night, he was treated like a toilet no better than an animal, and leading a life of spreading his legs. “Could it be… that you guys saved me?” The ones who rescued Sung-joon as he fled deep into the mountains to survive were not humans, but four-legged beasts.