“What?! I'm supposed to be the guardian of this tentacle monster?" In a research facility specializing in monster biology, Monster Veterinarian Doha finds himself under a slimy assault from a pubescent tentacle monster. During this encounter, the tentacle monster comes to recognize Doha as its 'maternal figure,' and he ends up becoming its guardian for a year, taking on the responsibility of its training. However, controlling this tentacle monster, which has an insatiable sexual appetite, proves to be nearly impossible on his own. Eventually, for safety reasons, he is introduced to Kyunghwan, the son of the research facility's director, as his partner. "Dr. Yoo, if it's okay with you… May I assist with the training?"