Yumen is a mobile fortress-city that sails across the desert. For nearly a hundred years, it's been guarded by a legendary martial arts grandmaster — everyone just calls him 'the Grandmaster.' As this story begins, he happens to be on the verge of retirement.

As luck would have it, right at this moment Yumen docks with its old sister city, Lungmen, and all sorts of people come pouring in. The Lungmen governor come to see off an old friend, a private detective searching for his missing sworn brother, and a desert girl clutching a single sword as she runs for her life.

Then that night, with a coincidence too perfect to be chance, three incidents erupt at once: an assassination attempt on the governor, the theft of the Grandmaster's beloved sword, and the massacre of a patrol outside the walls. With a Catastrophe bearing down, Yumen has no idea yet that all three are actually one and the same thread.

1. The First Night of Docking, Three Disasters at Once

On the inn's TV plays 《Storms Over Yumen》, a drama based on a real incident from fifty years ago — a tale of wandering swordsmen and soldiers joining forces to repel outside invaders. Except half the people in that story are sitting right here in this very inn, watching themselves on screen.

On the training grounds, the Filaine girl Waai Fu is sparring with a stranger from another people. Her opponent is Jieyun, who's just scaled Yumen's walls for the first time today — a girl of the nomadic Anasa tribe. Waai Fu wins in the end, but Jieyun only asks about a sword before disappearing.

Meanwhile, General Zuo's son Zuo Le has come home after a long absence, yet keeps putting off seeing his father. Up on the watchtower, the Grandmaster Chongyue is reminiscing with his little sister Ling.

A young man dressed in Sargonian clothes, claiming to be sightseeing in Yumen, adds to the chaos. In halting Yan, he boasts, "That Grandmaster taught me martial arts back in Sargon!" — only to get scolded by the innkeeper for mixing up the words for 'inn' and 'tavern.'

Night falls, and all three go off at once. An assassin trailing the scent of peach blossoms targets Lungmen governor Wei Yanwu; Jieyun steals Chongyue's sword and flees; and outside the walls, a Catastrophe-relay patrol is wiped out.

2. Zuo Le Gets Knocked Flat Before He Can Even Ask a Question

Having wounded the assassin badly, Zuo Le searches every clinic in Yumen for the culprit. At the last, run-down clinic he visits, a hulking man who won't even give his name turns him away at the door.

Zuo Le tries to force his way in with his martial arts, and gets knocked straight back out. The man, named Waai Tinfu, loudly declares he trusts nothing but his own fists — and Jieyun is already hiding inside the room.

But something about this man looks familiar. In fact, there's someone in this city who's been searching for him for over a decade. The story of a father who vanished, leaving his daughter behind, is something no one here knows yet.

It was this very giant of a man who'd secretly taken in and treated the wounded Jieyun. "Don't move. Just be still and let yourself heal." Gruff on the outside, he kept a straight face in front of Zuo Le right to the end.

3. The Detective and the Envoy, Chasing Different Shadows Through Yumen

The Lungmen private detective Lee has come to Yumen looking for a sworn brother from long ago. For days, all he's done is grab passing swordsmen and ask, "Have you seen a big, hulking man?"

At the same time, Lungmen envoy Lin Yusha is squeezing smugglers for information, chasing down the name 'Sanhaizhong.' It's supposedly a cult of bandits who worship the Behemoth — and they've targeted Yumen once before, twenty years ago.

In the marketplace, Zuo Le is ambushed by Sanhaizhong. Lee, passing by, steps in to help — and in the process, Zuo Le lets slip a crucial clue for the first time: "That big guy, he was a Filaine." Lee's expression goes still.

With that clue in hand, Lee finally tracks Waai Tinfu down, hiding in a clinic across from the inn. And by coincidence, an old friend also shows up there — Yang Xian, newly posted to Yumen as a magistrate.

It turns out Lee, Yang Xian, and Waai Tinfu swore brotherhood together over a decade ago. But their reunion over drinks is nothing but awkward.

"It's bad for my health." Waai Tinfu turns down even a drink, and Lee can only sigh. "Waai Tinfu, you idiot — same as any father, and yet somehow..."

4. The Rookie Courier Boss Picks Up an Armband

Du Yaoya, who came from Shangshu, has just opened 'Xingyou Logistics' in Yumen. Her very first job was escorting Catastrophe-relay couriers — and two of her own people were in that massacred patrol.

Du Yaoya and Waai Fu make the rounds of the victims' homes together and notice something strange: every single one looks untouched, as if nothing had happened.

Then an armband that Lin Yusha picked up from a blacksmith's storehouse points every suspicion in one direction — toward the elderly owner of the southside smithy, Meng Zheyi.

To Du Yaoya, Meng Zheyi is the only adult in Yumen she can truly rely on. But that night, as Du Yaoya and Zuo Le knock on the smithy's door, black-hooded figures burst out in front of them.

After the fighting, the person they find is Jieyun, wounded and hiding. The Grandmaster's disciple Qiubai arrives late and makes short work of the Sanhaizhong men — but Meng Zheyi, who should be at the center of all this, is nowhere to be found.

5. A Twenty-Year-Old Reckoning, Uncovered in the Storehouse

Lin Yusha comes face to face with Meng Zheyi in the storehouse. He hands over the real Catastrophe data without resistance and confesses everything: colluding with Sanhaizhong to fake the patrol's deaths, letting the Grandmaster's sword be stolen — it was all his own plan.

The reason goes back twenty years. After Sanhaizhong once infiltrated Yumen disguised as wandering swordsmen, General Zuo Xuanliao pushed every swordsman entirely out of Yumen's affairs. Meng Zheyi never forgot how those who'd bled for Yumen back then were cast aside.

"This whole affair started because of me, and me alone," Meng Zheyi says. But the one who comes for him isn't Sanhaizhong's boss — it's the true master who commands Sanhaizhong himself.

Xingyou Logistics was a fine idea... but even so, I couldn't just stand by and watch a fine young sprout get cut down right in front of me...

— Meng Zheyi

In front of Du Yaoya, who arrives too late, Meng Zheyi takes a blade meant for her back. Du Yaoya runs, clutching the data box to her chest, hoping that neither grudges nor apologies have come too late — not yet.

6. Father and Daughter, One Punch in the Middle of the Street

Sanhaizhong appears again, targeting Du Yaoya as she tries to protect the data. This time Waai Fu blocks the way — but her opponent's blade is strange, fast with no form at all, some bizarre kind of Originium Arts.

At the critical moment, a back like a wall steps in front of Waai Fu. It's her father, whom she hasn't seen in over a decade — Waai Tinfu.

Only after shielding his daughter does Waai Tinfu glance back. "Thanks for the save." "Nothing else to say?" "No need." After that short exchange, father and daughter trade a punch.

"I lost," Waai Fu admits first. But both of them know that the kick she landed on her father's chin wasn't something her father ever taught her.

7. Forty Years of Martial Arts, Settled with a Single Punch

Meanwhile, the Grandmaster's disciple Qiubai keeps a promise she made to herself. As a child, she lost her father when her river village was raided — and she's stayed at the side of Chongyue, who led that band of raiders, learning the sword from him for five years.

On the day the Catastrophe arrives, Qiubai points her sword at Chongyue, knowing full well she can't win.

I struck at you, and this strike failed to kill you. That I couldn't kill you doesn't mean I've given up on revenge — it's only that 'grudge' is no longer the reason I draw my sword.

— Qiubai

And then, another duel three years in the making. Waai Tinfu finally throws down his challenge to the Grandmaster, on the eve of the Catastrophe, under the pretext of a friendly bout to boost the soldiers' morale.

The Grandmaster wins. But Waai Tinfu, coughing up blood, still laughs. "Took me forty years just to beat one move of yours — give me three hundred sixty more, and I bet I'll win outright!" This man finds optimism in the strangest places.

8. The Catastrophe Descends, the Old Rat's Last Strength

The foretold Catastrophe finally bears down on Yumen. Instead of steering the city around it, General Zuo Xuanliao chooses to meet the Catastrophe head-on, right now, instead of waiting the usual two months.

One side of the gate is held single-handedly by the Grandmaster's sister, Ling. Cracking open a jar of liquor before a storm even hits is just her style. "Glad you came!" She takes on the Catastrophe swigging straight from the jar, no cup needed.

When the Astronomical Bureau casters guarding the core give ground, Lungmen's shadow, the Rat King (Lin Yusha's father), steps in himself. Everyone had taken him for just some old man who liked to take walks — but he shows the strength to push back an entire Originium storm.

But the cost of such an effort is steep. As her father collapses, coughing blood, Lin Yusha throws herself in front of him.

Enough talk. Everyone's hurt, so catch your breath. Not much further now. Eyes forward!

— Lin Yusha

9. What the Drawn Sword Revealed

In the middle of the Catastrophe, the unconscious Jieyun unknowingly draws the Grandmaster's sword. The moment she does, memories sealed within it come pouring out. Chongyue, it turns out, is one of twelve fragments of 'Sui,' a Catastrophe-class beast hunted down a thousand years ago, who split and sealed itself into pieces.

Chongyue has siblings beyond just Ling — Nian and Dusk among them. All of them are fragments of Sui, scattered across the human world in different forms.

And behind all this commotion was yet another fragment, 'Ya.' Badly wounded in that hunt a thousand years ago, he'd vanished without a trace — and had briefly used Sanhaizhong to pry into Sui's whereabouts.

Chongyue meets Ya in a vision, the two of them standing on a small boat, each on their own end, atop a frozen river.

You sealed yourself in a sword and took on a human body, just to think of yourself as one of them — and in the end, what did you get out of it?

— Ya

The Catastrophe isn't over yet. People don't even know you exist. Someone has to answer for Yumen's sake — and no matter how I look at it, there's no one left to do that but me.

— Chongyue

The conversation ends without resolution. Ya is sent flying with a single punch, and vanishes, leaving only the words: leave Yumen.

Chongyue says nothing at all. He knows well enough that every living thing facing death wears more or less the same face.

Epilogue: Everyone Lays Down Their Own Grudge

After the Catastrophe passes, everyone finds their own path forward. The sword leaves the Grandmaster's hands and passes to Waai Tinfu. "You may as well keep it as a token for our next match." The man who took forty years to win a single exchange accepts the sword, already looking forward to another forty.

Jieyun leaves the sword at a grave, only to come back for it and return it to its true owner — dimly realizing that the sword wasn't the only thing her master had missed.

Lin Yusha decides to stay in Lungmen instead of studying abroad in Victoria. "Whatever burden someone else sets down, someone else has to pick up." Waai Fu keeps training, promising her father a rematch, while Qiubai sets off with her sword in hand, in search of a new goal.

Waai Fu offers to pay off the rest of her father's medical bills for Lee, but the doctor just waves her off. "I figure saving and caring for people beats fighting all day, doesn't it." In the end, Waai Fu stays on and helps with the cleaning.

Last of all, Wei Yanwu shows the Grandmaster one final sword technique — the true final form of the Crimson Night Sword Style, 'Heaven.'

The sword moves with the heart, and there's no regret in a single stroke. The moment you hesitate, even slightly, the blade loses its edge and turns against you instead.

— Wei Yanwu

Before the gate, the Grandmaster runs into a stranger playing Go alone. He was, in truth, another 'sibling,' come to say a final goodbye.

Thanks to your sword, I learned something. We'll meet again. Farewell, sibling.

— a stranger's voice

Only then does General Zuo Xuanliao receive, from Lu Wuguan, the Grandmaster's final gift — a manual called 《The Manual of Martial Arts》, complete with breathing techniques for tempering the body through swordplay. By then, the Grandmaster had already left Yumen without a word of farewell, half a watch earlier.

For the first time in a hundred years, the Grandmaster leaves Yumen. As the eighteenth drumbeat sounds, General Zuo Xuanliao himself beats the drum of farewell.

The drama 《Storms Over Yumen》 told of swordsmen who laid down their grudges for the sake of the nation. Yumen's real story turned out no different. Around a single sword, everyone learned how to lay down a grudge of their own.