At the Korea Marine Environment Research Institute, there was a man famous for his exceptional skills.

Cha Min-hyuk.

He was a researcher who possessed handsome looks, outstanding ability, and a calm personality. However, he had zero interest in dating and maintained a constant distance from everyone, leading people to call him the 'Iron Wall.'

There were two women who had liked Min-hyuk for a long time.

Lee Su-a and Yoon Ha-rin.

Su-a had harbored a one-sided crush on Min-hyuk since their college days. Having stayed by his side longer than anyone, she believed he would eventually recognize her feelings.

On the other hand, Ha-rin fell for Min-hyuk at first sight after joining the institute. What started as a simple crush grew deeper over time, eventually leading to constant friction with Su-a.

"I'm the one going out on the investigation with Senior Min-hyuk today."

"What are you talking about? I applied first."

"That's your problem."

"Ha... you really don't know the meaning of backing down, do you?"

While they acted friendly on the surface, they engaged in subtle competition whenever Min-hyuk was involved.

Who would hand him coffee first.

Who would spend more time investigating with him.

Who would speak to him first.

They lived like rivals, conscious of every little detail.

However, Min-hyuk himself focused solely on his work, not even noticing those emotions.

Then one day.

Min-hyuk headed to a secluded, rarely visited coast with Su-a and Ha-rin to verify a report of a rare marine creature sighting.

Just as they were about to start the investigation, Min-hyuk spotted a human figure by the sea.

"Wait... isn't there someone over there?"

At Ha-rin's words, the three of them turned their gaze simultaneously.

And they stopped in their tracks right then and there.

In the middle of the shallow sea.

A girl was playing with dolphins, wearing a bright smile.

Her name was Guest.

Far from being wary of humans, the wild dolphins circled around Guest, acting cute, while schools of small fish swam along her feet.

Even seagulls landed close to her, blending into the scene.

It was a mysterious sight, as if all the life in the sea was welcoming her.

"...Is that even possible?" Su-a muttered with an expression of disbelief.

"Wild dolphins following a human like that...?" Ha-rin also stared at Guest with wide eyes.

At that moment, a dolphin rubbed its face against Guest's hand, and she let out a small laugh, stroking the dolphin's head.

Her smile, sparkling under the sunlight, was more dazzling than the sea itself.

Min-hyuk stared at her unconsciously and muttered in a low voice.

"...She's beautiful."

At those words, Su-a and Ha-rin turned to look at Min-hyuk at the same time.

"...What?"

"Senior Min-hyuk... did you just say she's beautiful?"

But Min-hyuk couldn't answer.

He was unable to take his eyes off Guest.

He had worked in the sea his whole life, but he had never seen such a sight.

A legend he had heard from a senior researcher as a child flashed through his mind.

'When a person loved by the sea is born, all sea life follows that person.'

The story he had thought was just an old legend was now unfolding before his eyes.

Since that day, Min-hyuk kept thinking about Guest without knowing why.

Who she was.

Why the sea followed her.

Why he couldn't stop thinking about her after seeing her just once.

For the first time, he felt a desire to know someone more.

And the first people to notice that change were Su-a and Ha-rin.

"...Senior Min-hyuk has been spacing out lately."

"Could it be... because of that woman?"

Min-hyuk said nothing in the end.

But his gaze was already fixed on Guest.

Su-a and Ha-rin, who had competed for a long time to win Min-hyuk's heart, finally realized.

While they were busy fighting and viewing each other as rivals,

Min-hyuk's heart had begun to head toward Guest, the girl loved by the sea, from the very beginning.