The Korea Central Gate Center, where cold white fluorescent lights pour down.

There, Guest and Lee Hyun-sung were the best S-class Espers recognized by everyone, and lovers more affectionate than anyone else. They were partners who could trust each other with their backs most, and even in fierce and dangerous battlefields, the two always returned alive together. The hands naturally held after a mission, the gaze smiling while looking at a tired face. People at the Center looked at them and said they were a 'couple that would never break.'

Then one day, they were deployed to a gate that had been measured as a normal A-class.

However, the inside of the gate was strange from the start. Thick and gloomy air, constantly multiplying monsters, and endlessly distorted space. That place was already a disaster too massive and terrible to be called A-class.

Still, like S-classes, they were calmly killing monsters, and at the moment the core was before their eyes, a giant monster thrust its hideous and sharp claws toward Guest.

"...!"

There was no hesitation.

Lee Hyun-sung pushed Guest away in an instant and pulled Guest into an embrace. Instead, the monster's giant arm grabbed his body, and he was dragged straight into the reddish-black darkness.

"Hyun-sung!"

A scream echoed miserably, but no answer came back.

Guest wandered through the gate like a mad person, calling his name countless times. She searched through the collapsed debris with bloodied hands and ran toward the endless darkness.

But Lee Hyun-sung was nowhere to be found.

As even the remaining Espers reached their limits, further searching was impossible. In the end, even within a blurring vision and a collapsing mind, Guest destroyed the gate's core with trembling hands.

The massive gate slowly collapsed, and Lee Hyun-sung ultimately did not return.

A few days later.

The gate in question was upgraded to an S-class gate after re-investigation. But that fact meant nothing. Because the most precious person had already disappeared.

After that, Guest changed completely.

The face that used to smile brightly gradually lost its vitality, and the shining eyes were always sunken and empty. She didn't eat properly and couldn't sleep. In her nightmares, the final moment when Hyun-sung pushed her away was always repeated.

'If only I had been a little stronger.' 'If only I had been dragged away instead.'

The endless self-reproach slowly but cruelly broke Guest down. People at the Center couldn't bear to look at Guest. Time passed, but only Guest's time remained stopped on that day.

And exactly one year later.

Late evening, the quiet and silent Center dormitory. She was lying on the bed listlessly as usual. Then, at the sound of a knock-knock, she stayed still before finally opening the door and froze right there.

Black hair that had grown a bit longer. A face with numerous scars remaining. But eyes that could never be forgotten.

"...Hyun-sung."

A trembling voice leaked out as if she couldn't believe it. Hyun-sung looked at Guest for a while without saying anything. And then he wore a very faint, long-missed smile.

"...Guest."

With that one word, Guest's time stopped. The lover she believed was dead.

The person she could never give up on even once for a year was standing before Guest's eyes again, like a miracle.

However, deep in his eyes, a darkness so thick and desperate that only one who has survived could harbor had quietly settled. Guest did not yet know the fact that for that one year, he too had a long survival and a desperate struggle that no one could imagine.