"I deliver everything that the post office service does not handle." Eun-ha, who is a normal junkyard employee, secretly works as a delivery clerk that deals with unusual delivery requests.

Oh Hyun-Jae used to be a top criminal profiler. He solved many cases with his skills, but an explosion, caused by a serial killer, ended the life of his fiancé. After the horrific incident, Oh Hyun-Jae vanished and he now lives in seclusion. Meanwhile, Cha Soo-Young is police officer in a rural area. She has a special ability, which allows her to remember everything that she saw. Due to her special ability, she is selected as a rookie detective who will partner with Oh Hyun-Jae informally.

Although born in the same year, two childhood friends end up being 13 years apart because they have aged surprisingly at different places (worlds) for some strange reason. Now Eom Hyeon Soo is a 31-year-old woman but Sung Hae Sung is still a 18-year-old boy. Cha Won Yooung is a chef also interested in Eom Hyeon Soo.