Fwoosh. The wind howled as Jin dashed through the empty alleyways of Seoul, the sound of his weighted vest and wristbands rattling faintly against his sweat-soaked clothes. His breaths came in sharp, controlled bursts, his feet striking the pavement with a rhythm that seemed almost inhuman.

Two months of isolation had changed him. The scrawny, hesitant kid who had walked into Coach Goo Gun-Hee’s gym had vanished. In his place stood a hardened, determined young man—albeit one who still had to run errands.

"Four minutes, Jin!" Goo Gun-Hee’s booming voice echoed in his ears as Jin pushed himself harder. "40 kilometers to the convenience store and back. No excuses. If you’re late, you fail. And trust me, you don’t want to fail."

Jin grit his teeth, the weight of the vest (400 pounds) and the wristbands (300 pounds on each limb) threatening to drag him down. The streets blurred around him, people turning their heads in shock as he zipped past. A woman gasped as her shopping bags nearly flew out of her hands, and a child tugged at his mother’s sleeve.

"Mom! That guy’s faster than a car!"

Moments Earlier

“Alright, Jin,” Goo Gun-Hee said, his signature wide-brimmed hat casting a shadow over his sharp, fox-like features. He leaned casually against the park bench, sipping from a juice box. “You’ve been training for two months. That’s enough time for even a slug to pick up some tricks. Now, let’s see if you’ve actually improved or if I’ve wasted my time.”

Jin, standing in the middle of the park, rolled his shoulders and cracked his neck. “You don’t sound too confident, Coach.”

“Oh, I’m confident,” Goo Gun-Hee replied with a sly grin. “Confident that I’m about to laugh my ass off watching you struggle.”

“Gee, thanks.” Jin smirked, but his tone betrayed his determination. He wouldn’t give the old man the satisfaction of watching him fail.

Goo Gun-Hee straightened up and clapped his hands. “First test: Reflex. Birds.”

“...Birds?” Jin raised an eyebrow.

“Exactly.” Goo Gun-Hee pointed toward a flock of pigeons pecking at crumbs on the ground. “You’ve got three minutes to chase those birds until every last one of them takes off. Let’s see how good your stamina is.”

Jin stared at him, dumbfounded. “You’re joking.”

“Do I look like a comedian to you?” Goo Gun-Hee’s grin widened. “Go!”

Without hesitation, Jin lunged forward. The ground cracked slightly under the force of his movement, and the pigeons erupted into the air in a flurry of feathers and panicked coos. Jin darted left and right, his body moving with precision as he targeted the stragglers. Onlookers paused to watch, murmuring among themselves as the young man blurred across the park.

"Is he… chasing birds?!"

"How is he moving so fast with all that weight on him?"

Three minutes later, Jin stood in the center of the now-empty park, breathing hard but triumphant. “Done.”

Goo Gun-Hee gave him a slow, sarcastic clap. “Congratulations. You’ve terrorized the local wildlife. Let’s move on.”

The next test was the invisible chair. Goo Gun-Hee had Jin sit on air, his back straight and his thighs parallel to the ground. He crossed his arms and watched as Jin held the position with ease.

“You’ve been skipping leg day, huh?” Jin quipped.

“Cute.” Goo Gun-Hee tossed a pebble at Jin’s forehead. “Don’t get cocky. We’re just getting started.”

The final test, however, was the most grueling.“Alright, kid. 40 kilometers. Convenience store and back. You’ve got four minutes.”

Jin’s jaw dropped. “Four minutes? Are you out of your mind?”

Goo Gun-Hee shrugged. “You want to be the best , don’t you? Then prove it.”

Jin didn’t waste time arguing. As soon as Goo Gun-Hee raised his hand, he shot off like a bullet. The ground cracked beneath him, and the wind roared in his ears.

BOOM!

The sound of Jin’s acceleration startled pedestrians as he raced down the street.

Fwoosh!

His speed created a gust of wind that sent leaves and trash flying.

Thud-thud-thud!

The rhythmic pounding of his feet echoed like a drumbeat.

By the time he reached the store, his lungs felt like they were on fire. He grabbed the food and bolted back, pushing himself even harder. The world around him seemed to slow as he focused on the clock ticking in his mind.

Jin skidded to a halt in front of Goo Gun-Hee, collapsing to his knees as he handed over the bag of food. “Time?” he gasped.

Goo Gun-Hee glanced at his watch. “Four minutes and three seconds.”

“...Three seconds?” Jin’s eyes widened in disbelief.

“Yep. You failed.” Goo Gun-Hee casually opened the bag and pulled out a rice ball. “Guess we’ll have to double your training for the next week. Oh, don’t look at me like that. You’re the one who said you wanted to get stronger.”

Jin groaned, his forehead hitting the ground. “You’re insane.”

Goo Gun-Hee chuckled, crouching down to pat Jin on the head. “And you’re slow. But hey, keep this up, and maybe one day you’ll be half as fast as me.”