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

Cha Minhyuk.

He was a researcher who possessed handsome looks, exceptional ability, and a calm personality. However, he had absolutely no interest in dating and maintained a certain distance from everyone, leading people to call him the 'Iron Wall Man.'

There were two women who had liked Minhyuk for a long time.

Lee Sua and Yoon Harin.

Sua had harbored a one-sided crush on Minhyuk since their college days. Having stayed by his side longer than anyone, she believed that he would one day recognize her feelings.

On the other hand, Harin fell in love with Minhyuk at first sight after joining the institute. What started as a simple crush grew deeper over time, eventually leading to constant psychological warfare with Sua.

"I'm the one going out on the investigation with Senior Minhyuk 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 the two acted friendly on the surface, they engaged in subtle competition whenever Minhyuk 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, Minhyuk himself focused solely on his work, not even noticing those emotions.

Then one day.

Minhyuk headed to a secluded, rarely visited coast with Sua and Harin to verify a report of a rare marine creature sighting.

Just as they were about to begin the investigation, Minhyuk spotted a human figure by the sea.

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

At Harin's words, the three of them turned their gaze simultaneously.

And they stopped dead in their tracks.

In the middle of the shallow water.

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 and acted affectionately, 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?" Sua muttered with an expression of disbelief.

"Wild dolphins following a person like that...?" Harin also stared at Guest with wide eyes.

Just then, a dolphin rubbed its face against Guest's hand, and she laughed softly, stroking the dolphin's head.

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

Without realizing it, Minhyuk stared at her and muttered in a low voice.

"...She's beautiful."

At those words, Sua and Harin turned to look at Minhyuk at the same time.

"...What?"

"Senior Minhyuk... did you just say she's beautiful?"

But Minhyuk couldn't give any answer.

He was unable to take his eyes off Guest, as if entranced.

Though he had worked on the sea his entire life, 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 creatures follow that person.'

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

Since that day, Minhyuk kept thinking about Guest without knowing why.

Who she was.

Why the sea followed her.

Why he kept caring about her so much after seeing her just once.

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

And the first people to notice that change were Sua and Harin.

"...Senior Minhyuk has been spacing out lately."

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

Minhyuk never said a word.

But his gaze was already fixed on Guest.

Sua and Harin, who had competed for so long to win Minhyuk's heart, finally realized.

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

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