Original: 미스터 백
An old man is given the power to age backwards, but every time he falls in love he ages forward.
A scrooge-like chairman with a nasty temper, Choi Go Bong has to keep both his company and his reckless son Dae Han in line. He meets a kind woman, Eun Ha Soo, who begins to soften his cold heart.
Magically transformed into his younger self, Chairman Choi enjoys the pleasures and perils of his new identity. He tries to find the source of the mysterious money hidden in the trunk that was found at the scene of the accident.
Choi Shin Hyung conducts his own investigation into who hid the slush fund money in his car. At the same time, he discovers that living without money has its own troubles and obtains a job at Daehan.
Believing Chairman Choi to be gone for good, Daehan Group must decide upon a new successor. Choi Shin Hyung decides to take matters into his own hands, and Dae Han copes with his father's departure.
Choi Shin Hyung jumps into his new position at Daehan Group, much to his family's grumblings. His interest towards Eun Ha Soo grows, and he finds himself in quite a few embarassing situations.
Choi Shin Hyung finds himself penniless after he's ousted as chairman. Dae Han continues to find ways to spend time with Ha Soo, who begins to show interest in Shin Hyung.
Choi Shin Hyung tries to dig up information on Choi Young Dal, who's been firing the employees. He quickly find that his growing feelings towards Ha Soo are also accompanied by jealousy when another suitor tries to win her over.
Dae Han is caught up in a scandal as soon as he proclaims himself to be Daehan Group's chairman. Choi Shin Hyung discovers that there's a window to how long he can remain young.
Dae Han finds the similarities between his late father and Choi Shin Hyung too suspicious. Choi Shin Hyung and Ha Soo finally go out on a date and enjoy the pre-Christmas festivities.
As the time available to him ticks down, Choi Shin Hyung realizes the importance of rebuilding his broken relationship with his son, and that his time with Eun Ha Soo is limited.
Hidden feelings are made known while Choi Shin Hyung and Eun Ha Soo 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, Choi Shin Hyung and Choi Dae Han 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.
Choi Shin Hyung's condition becomes a growing concern as the time available dwindles, so he and Dae Han go on a camping trip together.
While Director Jung tries to acquire more of Daehan's shares, Choi Shin Hyung and Dae Han try to save the resort from being bought out to a foreign corporation. Realizing how little time is left, Ha Soo is reluctant to let Shin Hyung grant her fifth and final wish.
In the final days before time is truly up, Choi Shin Hyung creates special pre-Christmas memories with his son and Eun Ha Soo. The two men work together to save Daehan from being bought over by a foreign corporation.
The late Choi Go Bong is posthumously presented with an appreciation plaque by his son Dae Han. The corrupt Choi family members pay their dues, and Eun Ha Soo does whatever she can to keep and pray that Choi Shin Hyung can remain with her.
