Luke transmigrates into the world of One Piece and obtains the [Legendary Recruitment System]. He thinks he’s gotten a winning start from the start, but every crewmate he recruits turns out to be a “problem senior”: a frail cook, a swordsman who gets lost, a timid navigator, and a sleepy sniper. As pirates of all stripes mock them as a “retirement home at sea,” Luke only wants to keep the old-timers safe on their voyages.
But when a Marine Admiral leads a Buster Call fleet to hunt them down, the crew members who usually can’t even twist off a bottle cap finally stop pretending. The frail cook sends a flying kick that cleaves through the waves, and is recognized as the missing chief instructor of the Revolutionary Army. The directionally challenged swordsman casually swings his blade, slicing an island in two with his sword aura. He turns out to be the junior disciple of the World's Greatest Swordsman.
Only then does Luke realize that his crewmates are all legendary figures from the previous era who chose to retire. The purpose of his System is revealed as well: he isn’t meant to help them enjoy retirement, but to help them resolve their regrets, rekindle their passion, and stand once more at the summit of the world. As one legendary identity after another comes to light, this unassuming “retirement ship” gradually becomes a vast whirlpool that stirs up the balance of power in the New World, attracting the close attention of the Marines, the Four Emperors, the World Government, and even the Revolutionary Army.
