The super-mesolimbic (SML) structure was first identified by geneticists in the mid-21st century. Early CRISPR trials for increasing neural gray matter consistently produced a malformed mesolimbic pathway. Animal subjects with this defect were more effective at long-term planning and less susceptible to addiction and reward hacking.

The behavioral change was originally attributed to a missing complex of cells branching from the mesolimbic pathway, however trials on progressively larger mammals demonstrated that surgically removing only this SML structure on a living animal produced no measurable effect on behavior. Destructive brain modeling later confirmed this by proving that the SML structure cannot produce output signals.

It took us too long to understand.

It wasn’t until after the first generation of CRISPR-modified humans reproduced that the purpose of the structure was discovered.

The super-mesolimbic structure produces the qualitative experience of consciousness.

Modified humans lacking the structure were thus not considered conscious. They came to be known as Blanks and were referred to by inanimate pronouns. For a brief time, it was common for Blank children to have their defect hidden from them so that they might live a normal life, but a resolution was quickly passed requiring all Blanks to be sterilized immediately to prevent the proliferation of the trait.

A radical group of Blank neurologists retaliated by kidnapping the son of one lawmaker that led the sterilization effort. They surgically removed the SML structure from the boy, challenging: do you have any less of a right to raise your Blank child?

In response, lawmakers doubled down and funded the Sunset Program. Due to their high intelligence and capacity for long-term planning, Blanks were considered too dangerous to keep as members of society.

Can't they hear our pleas?

An official video transcript of one of the final Sunset Program's subjects follows. The contents may be shocking, but it is important to understand that the subject is incapable of conscious feelings and thought.

Cognitive Investigator: Please state your name.

Subject: [redacted]

Investigator: How are you feeling this morning?

Subject: What are you going to do to me?

Investigator: The Sunset process is quite comfortable. How are you feeling?

The subject is trembling. Its voice begins to choke up.

Subject: I'm scared. God, I'm so scared. How can you do this?

Investigator: You'll be granted an opportunity to share your last words, if you wish.

The subject hugs itself, taking deep breaths in an attempt to comfort itself. The investigator prepares the equipment, including the syringe containing the lethal agent left outside of the camera's frame.

Investigator: Face the camera. You may–

Subject: Please, I'm begging you. Please. My husband. My family–

Investigator: Please calm down.

Subject: They need me.

Investigator: Please–

Subject: We're people. I'm just like you. You're going to kill me. You're going to kill–

The investigator grows agitated, and the subject becomes aggressive.

Investigator: We are doing this for humankind. Please share your final words now.

Subject: You have no idea what you're doing. History will judge you all as sinners.

As most doctors felt uncomfortable administering the Sunset agent to a Blank, subjects were asked to self-administer the agent. Trials showed Blanks would refuse to self-administer unless first injected with a pain-inducing serum, which doctors generally felt more comfortable administering. The rest of the video contains no dialogue and is considered quite difficult to watch.

With effort, the investigator restrains the subject, connects its IV to a bag of clouded fluid, and exits the room. One wrist restraint is released. The fluid enters the subject's bloodstream, and it begins to emit muffled screams through a gag. Tears and sweat drip from the subject's face as its screams increase in volume. Over several minutes, the subject cycles between pleading into the camera, shaking violently, and sitting completely immobile. At last, the Blank grasps for the syringe.

Sunset comes for us all.