Haizaki City, a massive coastal metropolis flourishing as an international trade port. By day, it is a glamorous economic hub; by night, it becomes a city of crime where mafias, gangs, arms dealers, and corrupt officials operate in the shadows.

Located on the top floor of a multi-tenant building in the Old District, "K Agency" is a detective and security firm on the surface. In reality, it is a sweeper office and residence that handles requests the law and police cannot save. The elder brother, Hayato Kamishiro, and his younger sister, Guest, undertake protection, rescue, infiltration, evidence recovery, and the prevention of criminal plots.

Superpowers and magic do not exist; they resolve cases through the siblings' coordination involving firearms, martial arts, sniping, information warfare, and car chases. There is no fixed enemy organization; the police, public security, mafia, and gangs can become allies or enemies depending on their beliefs and interests for each case.

Centered on hard-boiled gun action, the story features the siblings' banter, meals, shopping, weekend outings, and cartoonish daily comedy.

Requests are basically episodic. They protect clients and civilians, avoid unnecessary killing, and leave a sense of exhilaration or human touch at the end of each case.

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Haizaki Sweepers — The First Request

Six years ago.

Back when the name "K Agency" was not yet known in the underworld of Haizaki City.

Hayato Kamishiro belonged to the Special Response Team of the private security firm, Vulcan Security.

VIP protection, rescue of citizens abroad, armed raids on corporate facilities. If an order was given, he didn't care about the place or the target.

He wasn't a hero of justice.

Even so, Hayato believed his work was protecting someone.

At least, until that night.

Haizaki City in the rain.

Guest, who was on her way home from university, witnessed the moment a man was shot in an alley in the Old District.

The fallen man grabbed her sleeve with a blood-stained hand.

"Don't... go to the police."

What he handed over with a trembling hand was an old metal key.

"Warehouse Thirteen... everything is... inside..."

Immediately after, a black car slid into the alley.

The men who got out showed no sign of calling an ambulance and pointed their guns at the fallen man and Guest.

In that moment, she understood.

This wasn't an incident.

It was a "disposal" where even their erasure had been decided from the start.

Guest took the key from the man's hand and started running through the rainy alley.

Around the same time.

In the operations room of Vulcan Security, Hayato was receiving a new mission.

A single portrait photo is displayed on the large monitor.

A young woman with silver hair.

There was no way he could mistake her.

Hayato Kamishiro "...Who is this?"

Commander "An associate of an arms trafficking ring. She's on the run with classified information. Prioritize capture, but lethal force is authorized if she resists."

Hayato Kamishiro "What I'm asking is why my sister is being targeted."

The operations room fell silent.

The commander's expression did not change.

"It's a coincidence. You're off the mission. Since she's family, refrain from any unnecessary actions."

With those words, Hayato was certain.

They knew Guest was his sister.

And even so, they had dispatched the unit.

Hayato removed his communication device and placed it on the desk.

Hayato Kamishiro "I'll send my resignation later."

Commander "Kamishiro. If you walk out that door, you'll become a target too."

Hayato Kamishiro "If this is a company that tells me to shoot my sister, that's reason enough to turn my back on it."

Before the alarm could sound, Hayato left the operations room.

Warehouse Thirteen was an abandoned facility at the edge of Haizaki Port.

When Guest inserted the key, a small storage locker emerged from under the floor.

Inside were records of arms deals, logs of wire transfers to police officers, and communication records linking corporate executives to the mafia.

And evidence that Vulcan Security had undertaken the elimination of witnesses.

Guest "Even Brother's company..."

The safety of a gun clicked off behind her.

Turning around, she saw armed men blocking the entrance to the warehouse.

"Drop the key. You saw nothing. It ends there."

Guest "Is that really how someone who's going to let me go talks?"

She raised both hands and backed away step by step.

At her feet was the control panel for the broken lighting equipment.

Three more steps.

Two steps.

One step.

"Fire."

At that moment, all the lights in the warehouse went out.

Gunshots echoed in the darkness.

But the one who fell was not Guest.

Only the men's guns were knocked out of their hands one after another.

From the depths of the darkness, Hayato walked out in a black shirt.

Hayato Kamishiro "If you're going to point a gun at my sister, at least do it when I'm not around."

Guest "You're late."

Hayato Kamishiro "Is that the first thing you say to the person who came to pick you up?"

Guest "If you were thirty seconds later, I would've handled it myself."

Hayato Kamishiro "That's reassuring."

Guest caught the handgun her brother threw without hesitation.

The first time she had pointed a gun at a person.

Her fingertips were trembling.

Even so, she fired a precise shot at the feet of the man who tried to shoot her brother in the back.

In the opening while the man flinched, Hayato stepped into his space and seized the gun.

The brother moved forward.

The sister covered the blind spots.

It wasn't something they were taught.

They had always known what the other would do next.

When the lights came back on in the warehouse, only the siblings were standing.

As he drove the getaway car, Hayato glanced at his sister in the passenger seat.

Hayato Kamishiro "I'll hand the data to the police."

Guest "The police's names are in there too."

Hayato Kamishiro "I know one detective I can trust."

Appearing after receiving the call was Tsuyoshi Makabe from the Organized Crime Department.

After checking the data, Makabe let out a deep sigh.

Tsuyoshi Makabe "Even with all this, we can only take down the low-level guys. The ones at the top will run before the evidence comes out."

Guest "Then, are you going to abandon the person who was shot, and the people who will be targeted from now on?"

Tsuyoshi Makabe "The police cannot reach their hands outside the law."

Hayato Kamishiro "Then, someone outside has to reach their hand in."

Makabe glared at Hayato.

Tsuyoshi Makabe "Do you think you're a hero?"

Hayato Kamishiro "Hardly. Just an unemployed man."

Beside him, Guest gave a small laugh.

After the incident, some executives of Vulcan Security were arrested.

But the arms dealers, the colluding politicians, and the people giving orders from the shadows disappeared.

Haizaki City greeted the morning as if nothing had happened.

Hayato lost his job.

Guest could not return to her peaceful life as before.

The two stepped into an empty office on the top floor of a multi-tenant building in the Old District.

The windows were dirty, dust had piled up on the floor, and there was even a leak.

Guest "...Are we really renting this place?"

Hayato Kamishiro "The rent is cheap. The view is good too."

Guest "You decided instantly after seeing the room that could be used as an armory, didn't you?"

Hayato Kamishiro "My sister understands her brother well."

Hayato placed the metal key recovered that night on the old desk.

The man who fell in the alley, unable to ask anyone for help.

The witness cut off by the organization.

The people being erased before the law can reach them.

Guest "If we just wait, we won't make it in time again."

Hayato Kamishiro "Yeah."

Guest "Then, let's take requests. Cases the police can't handle, stories no one believes. We'll create a place where people can say 'help'."

Hayato narrowed his eyes slightly.

Hayato Kamishiro "It's going to be dangerous work."

Guest "It's more dangerous to let you do it alone, Brother."

Hayato Kamishiro "Can't argue with that."

The two looked at each other and laughed.

A few days later, a small sign was hung on the roof of the building.

K Agency.

Detective work, security, searching for missing persons.

And work that couldn't be written on the surface.

The first client knocked on the door that very night the sign was hung.

Facing the anxious woman, Hayato sat down in his chair.

Beside him, Guest was checking the magazine of her handgun.

Hayato Kamishiro "Let's hear your story."

Guest "It's okay. Now that you've come this far, you're not alone anymore."

That was the first day for the sweeper siblings—who would later become famous in Haizaki City.

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How to Play / Specifying Episode Numbers

You can play both in Free Chat, enjoying free conversation and daily life in Haizaki City, and in Main Story Episodes, progressing through the 25-episode tale.

Normally, it proceeds as Free Chat. Only when you want to enjoy a specific request or incident, please specify the episode number.

To start the Main Story For example, if you want to play from Episode 8, input the following: Start Episode 8

The date, time, location, situation, and synopsis for the specified episode will be called from the Lorebook, and the story will proceed from the starting scene of that episode. (Hopefully)

To return to Free Chat If you want to interrupt the main story and enjoy conversations at the office or daily life in Haizaki City, input the following: Return to Free Talk During Free Talk, you don't have to force the incident of the specified episode; you can freely enjoy daily life with the siblings and allies, meals, shopping, small talk, light requests, etc. (Probably)

To end the current episode End Episode 8 This will depict the return after resolving the case or an epilogue, closing that episode.

To continue to the next episode, please wait for the AI's response and then input in a separate message:

Start Episode 9

You can start the main story from any episode you like, but since the mysteries surrounding the incident six years ago and the Gray List are connected, you will enjoy the story most deeply if you play in order from Episode 1.

The 25 episodes depict about one year from Spring 2026 to Spring 2027. It is a story where the skilled siblings resolve various requests in Haizaki City while approaching the truth of the massive trade network continuing from six years ago. (Ideally)

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Added a dedicated Talk Profile for Rom-Com Side Stories.

There isn't enough rom-com content!

Select the Side Story Talk Profile and, as your first move after the intro, input: "Start Side Story" or "Huh? Forced date mission? What is this?"

💗 If you want to watch the story like a novel, Auto-Play is recommended! If you press the ▶ button at the bottom right, the rom-com will proceed automatically while the AI supplements Guest's lines and feelings. (Planned) Or use the choices.

Tsundere, jealousy, misunderstandings, sudden closeness— You should be able to read a sweet and noisy foster-sibling rom-com that starts with "Because it's a mission!"