Mr. Back Season 1

A scrooge-like chairman with a nasty temper, Chairman Choi Gobong, has to keep both his company and his reckless son, Choi Daehan, in line. He meets a kind woman, Eun Hasoo, who begins to soften his cold heart.

Magically transformed into his younger self, Chairman Choi enjoys the pleasures and perils of his new identity, Choi Shinhyeong. He tries to find the source of the mysterious money hidden in the trunk that was found at the scene of the accident.

Shinhyeong conducts his own investigation into who hid the slush fund in his car. At the same time, he discovers that living without money has its own troubles and gets a job at Daehan.

Believing Chairman Choi to be gone for good, Daehan Group must decide upon a new successor. Shinhyeong decides to take matters into his own hands, and Daehan copes with his father's departure.

Shinhyeong jumps into his new position at Daehan Group, much to his family's grumblings. His interest towards Hasoo grows, and he finds himself in quite a few embarassing situations.

Shinhyeong finds himself penniless after he's ousted as chairman. Daehan continues to find ways to spend time with Hasoo, who begins to show interest in Shinhyeong.

Shinhyeong tries to dig up information on his brother, Choi Youngdal, who's been firing the employees. He quickly finds that his growing feelings towards Hasoo are also accompanied by jealousy when another suitor tries to win her over.

Daehan is caught up in a scandal as soon as he proclaims himself to be Daehan Group's chairman. Shinhyeong discovers that there's a window to how long he can remain young.

Daehan finds the similarities between his late father and Shinhyeong too suspicious. Shinhyeong and Hasoo finally go out on a date and enjoy the pre-Christmas festivities.

As the time available to him ticks down, Shinhyeong realizes the importance of rebuilding his broken relationship with his son, and that his time with Hasoo is limited.

Hidden feelings are made known while Shinhyeong and Hasoo continue their relationship. However, they find that they face opposition along the way and achieving happily ever after is easier said than done.

Left heartbroken, Shinhyeong and Daehan finally spend time with each other and enjoy each other's company. The two men also join forces to prevent Seohae Hotel from being converted into a premium outlets facility.

Shinhyeong's condition becomes a growing concern as the time available dwindles, so he and Daehan go on a camping trip together.

While Director Jeong Yigeon tries to acquire more of Daehan's shares, Shinhyeong and Daehan try to save the resort from being bought out to a foreign corporation. Realizing how little time is left, Hasoo is reluctant to let Shinhyeong grant her fifth and final wish.

In the final days before time is truly up, Shinhyeong creates special pre-Christmas memories with his son and Hasoo. The two men work together to save Daehan from being bought over by a foreign corporation.

The late Chairman Choi is posthumously presented with an appreciation plaque by Daehan. The corrupt Choi family members pay their dues, and Hasoo does whatever she can to keep and pray that Shinhyeong can remain with her.