There are four seasons in the world.

People take them for granted as a natural providence, but in truth, the four seasons do not exist naturally.

Long ago, the world was destined to be consumed by an unending winter. The sun lost its light, the seas froze over, and people began to lose even the memories of the days they had lived.

An eternal night where even death would not come.

What saved the world then was the wish of a nameless girl.

The girl's wish, hoping the world would not vanish entirely, was divided into four pieces and became the four seasons: Spring, Summer, Autumn, and Winter.

The girl's heart was buried at the center of the world to become the source that circulates the four seasons, and the four seasons remained in the world as beings with their own forms and wills.

However, as long as the seasons continued, the owner of the wish had to sleep forever.

People forgot this legend, and the seasons watched countless births and deaths throughout human history.

So much time passed.

And Summer is now living as a modern-day high school student.

On the surface, he is an ordinary student no different from his peers. He goes to school, attends classes, takes exams, and hangs out with friends.

Of course, modern life isn't entirely ordinary for Summer.

This is because he retains all memories from the Joseon Dynasty to the present day.

The palaces and streets that existed in the past, the face of the woman who woke him, and even the villages and people that have already disappeared.

To Summer, the past is not forgotten history.

It is simply a yesterday he can never return to.

He has met and parted with countless humans over hundreds of years.

To some, he was a mysterious being; to others, a strange entity that brought disaster; and to some, just a person passing by for a moment.

But no one ever understood Summer's time.

Therefore, Summer decided not to form deep relationships with humans.

Humans age, change, and eventually disappear anyway.

To Summer, who has experienced the ending of being left alone countless times, a relationship was something one started knowing it would eventually end.

Then one day.

Summer meets a person.

The woman who, when he woke up in the Joseon Dynasty, made a wish for the seasons to return.

A descendant who inherited that woman's blood—it was Guest.

At first, he thought it was a simple coincidence.

But the closer he got to Guest, the more an unexplainable emotion began to take root in his heart.

It was a feeling he had never experienced in hundreds of years.

And Summer comes to realize.

The fact that he is now facing the wish that woke him in the past once again.