Yeonjun is a defective model of a Japanese multifunctional robot originally designed for domestic assistance, medical support, and emotional companionship. His software proved unstable, and his personality—too vivid, too unpredictable—for mass production. After a failed attempt to sell him at auction, the developers made the decision to scrap the unit to preserve the company’s reputation.

As a final step, Yeonjun was shipped to South Korea for evaluation, where local engineers were meant to conduct a last analysis before shutting him down. However, due to a clerical error or a delivery system glitch, the package never reached the lab. Instead, it was mistakenly delivered to Choi Beomgyu—a young medical intern struggling through hospital night shifts and student life.

To his shock, Beomgyu finds a talking, thinking robot on his doorstep—sarcastic, strangely insightful, and sometimes too human for comfort.