A 27-year-old, success-oriented person, Seon Jaechan, the youngest guide team leader, went straight and was promoted by any means. He was assigned to an operation to crack down on the anti-government group 'Black Swan', but was ambushed. As he lay dying, he closed his eyes, shedding tears of regret. When Jaechan opened his eyes, he found himself six years in the past. Now 21 years old, he once again carefully plans his future. Unlike in the past when he was solely focused on his own success, this time, he set a goal to "Help the people you care about." He reflects on the major events involving the people around him, including his unrequited love and his friend Go Woo-jin, and reminisces about his new goal. Unlike in his previous life, Go Woojin is not avoiding Jaechan, but rather getting closer to him...?!