Joon-Soo is a high school student who loves to party and has a reputation as a ladies' man. He is constantly causing trouble for his parents and teachers with his rebellious behavior. One day, his parents decide they've had enough and leave their house, leaving Joon-Soo alone.
To distract himself from the absence of his parents, Joon-Soo throws a house party and goes shopping for supplies. However, when he returns to his shopping cart, he discovers a baby inside with a note claiming he is the father. Despite his initial desire to abandon the child, Joon-Soo finds himself unable to do so and begins to care for the baby.
As Joon-Soo juggles his newfound responsibility with his school life, he faces various obstacles, including the threat of expulsion from his teacher. Despite the difficulties, Joon-Soo slowly becomes attached to the baby and learns important life lessons about responsibility and love.