Deep, deep underground there was a secret laboratory hidden from the world. A place where inhuman experiments were conducted while being trapped inside the walls like rats. Not even a kind-hearted monster would dare step foot inside this laboratory. No windows or doors to escape from or let an ounce of warm light from the outside world inside. Fluorescent bulbs were the only source of light of hope to fight off the cold darkness. It couldn't keep away the haunting memories of death and unhappiness echoing through the walls. Not even a smile could wash the painful cries of a child's voice as it bouncing off the wall. Inside a large white room, a test subjected was being prepared for the experiment. The floor was covered with tubing and wire hooked up to a mechanical machine. In the center of the mess was a tall thin skeleton in a lab coat leaning over a strange human-like creature on an operating table. The first glace it appeared to be the corpse of a little girl, who had the right side of their flesh completely cleaned off, down to the bone. The left side of the chest was still cover in in soft pink flesh moving up and down with every gasping breath the child took. Whimpering a bit between breaths as their finger rubbed on the smooth surfaces of the cold metal table. She begged for the freedom to move her hands and find the words to speak. The poor thing couldn't move a muscle, as its arms and legs were bound by metal cuffs pinning the body down to the table. Hours of crying had left the throat dry to the bone. Uttering even a sound caused a scratchy burning sensation that swells up in the mouth and throat. In the corner of her left eye, she watched as the skeleton figure turned his back while he messed around with medical instruments layout on the metal tray that was connected to a stand.

"D…A...D...D….Y"

"SUBJECT TWO..." the skeleton yelled, smacking his hands against the tray as orange-blue lights flared up in the eye sockets causing the table to bounce as a few pieces of equipment hit the flooring. The bony hands clutched into tight fits as the rest of their body rattled in anger. "I told you repeatedly to not to call me that…You are to refer to me as Dr. Gaster, or doctor, nothing else." He demands in a harsh voice, noticing a dark shadow figure leering in the corner of the room. It didn't say a word as its yellow orbs watched every movement the doctor made. Gaster groaned in bitterness trying to ignore the spectator as he went back to work. He picked up a syringe filled with mysterious liquid the same color as human blood, but tinnier and glowed as it cast a red reflection over the heartless skeleton's face.

"NO…MO…RE…PL...E…" Subject Two pleading, turning into a fit of coughing as Gaster gently pinched the skin on girl's arm. The human-skeleton girl cried in fear as the tip of the needle pierce the skin. Another cry was about to escape her lips, but it stopped as a happy chiming noise buzzed in her ear. She slowly opened her eye watching as the wicked skeleton doctor quickly placed the syringe onto the steel tray and walking out of the room. Paying no mind to the darkly hooded creature, who was still leering in the room and left alone with the poor child.

The happy melody stopped for a second before the tune started back up from the beginning of the song as the skeleton walked down the hallway into a room smaller than one he had been previously. Unlike the other room which gave off creepy vibes of a laboratory built by Dr. Frankenstein, this one was simply a messy office with many bookcases. Gaster walked over to the computer table littered with stacks of paper. A bone hand dug into the pile, causing the happy melody to became loud as a bright light flashed under a few scraps of paper. Under the mess was a black flip phone which he quickly flipped open and press against the side of his skull discovering a tiny young male voice calling out for their father.

"Sans...I know...I'm sorry ...I have to work late. I need to get this done for the King, by tomorrow..." The skeleton sighed as his fingers tapped on the desk waiting for the voice on the line to stop pleading for him to come home. He hated leaving his children alone unprotected during the night but work came first. "I promise to tell you everything...Just not yet...You're eight years old now, so be a big boy for daddy...There is a can of spaghetti you can heat up in the microwave...make sure Papyrus goes to sleep. I don't want him playing with his Rubik's cube all night again...Yes...I will make sure to buy ketchup on my way home. Good night, I love you both." he whispers the last words before flipping the cell phone closed with a deep sigh, turning the phone into silent mode and placing back it on the desk.

It didn't take long for Gaster to return to the room where his test subject was waiting. She looks up at him with her tired sleepy one purple eye. Darkness and despair eat away at the orange-blue soul, burning in pain as it pushed against his rib cage. The cold boney body turned away ignoring the whimpering painful noise that slipped from the child's pleading lips. A hand hovered over the tray stand as fingers lightly brushed the red syringe as he looked at the other five empty syringe barrels next to it. Night after night, he caused this poor girl pain as he injected her with different soul traits. Tonight, he was hoping it would be the last time he had to do this. All their hopes rest on this little human-skeleton to save all of monsters kind. He couldn't wait for the three other humans to fall into the Underground. There was no telling if the others would fall anyway. What if humans were already wiped off the face of the earth?

Gaster looked down at the holes in his hands as he wiped purple tears from the girl's eye. The experiment was already this far along, so why should he stop now? He needs to save everyone. Even if it meant killing his own…The skeleton shook the dark thought from his mind. Test subjects were expandable. This child didn't belong to the monster world or the human world. There was no place for this hybrid outside the laboratory walls. He promised to show his children real stars someday on the surface. First, he needed to break the barrier that imprisoned the monster race in the Underground.

"I'm sorry my child, but we need you. If this works, we will not need to wait for the last remaining souls, to break the barrier? Just you and combined soul traits inside of you…" the skeleton said while injecting Subject Two with the soul-trait of determination. A chilling scream echoed off the walls as a sharper pain shocked through the child's body. Purple fire flared from girl's right socket as the head tossed to the side, writhing in pain. A high-pitched screech pierced the eardrums as her fingers nails scrape across the metal operating table. Gaster took a step back watching in horror as the test subject's left eye glazed over and child's expression went blank and tensed up. He quickly pulled the resuscitator over and carefully opening the child's mouth. A plastic mask was placed over the subject's mouth and releasing clean air into the chamber. No response as two bony hands, one on top of the other placed over the middle area of the girl's chest, pushing down hard over and over, but nothing change. "WAKE UP!" He screamed while blue light shimmered under the child's clothing as he used magic to put presser on the girl's soul.

Piercing shrill of pain filled the air as the blue magic released the captivity soul. Subject Two heavily breathed while sweat dripped down their face, drenching her rave hair underneath her head. The cloudy eye came back into focus as a crimson red ring glowed around the purple iris and dark purple orb glowed in the right eye socket. A half smile spread across the human side of the face as Gaster removed the breathing mask. Her lips trembled slightly as her mouth opened. "I'm al…rig… ht…Da…Doc…tor….It dos.. en't hu..rt any…more" She spoke in a weak voice as the sound of bone-rattling came from under her grayish medical gown.

The skeleton sighed in relief as the dark aura left the room he slightly looked over his shoulder discovering the corner of the room was now empty. It was only the two of them now as the skeleton leaned over carefully and took hold of the child's tiny right bony white hand within his own bony hand. "The soul level was too low right now to precede with the next operation of the plan…It will have to wait until morning." Letting go of the child's hand "I need you at full strength…" Gaster deeply sighed while undoing the metal cuff binding the girl to the operating table. "Getting some rest is the best course of action...All of our hope rests on you….I can't afford to fail… After all, you're part of both worlds…" arms slowly slipped under the child's head supporting it as the tiny body lifted off the table and cradled in the doctor's arms. "My little angels" Gaster whispered softly into the sleepy girl's ear as they walked out into the hallway to an unknown part of the Secret Laboratory.

Nothing changed in the Underground. The barrier that imprisoned the monsters was never broken, leaving the humans the sole race to rule the surface. So the trapped creature's lives stayed the same as they lived out their mundane lives, except for two little skeleton brothers. A tiny dark empty hole of loneliness grew in the children's heart. Their father, the Royal Scientist was known to leave the boys alone and not come home for few days, but those days quickly turned to weeks. Dr. Gaster was soon claimed as missing, disappearing without a word to anyone. A search party was sent out to find him. There was no sign of him, not even a bone. A month come and gone as another scientist was appointed the title "Royal Scientist" and took over the absent doctor's research and laboratory. The secret experiment plan to free everyone vanished. Ten years went by and two more human souls were captured. Which was wonderful for everyone; except for two brothers who really just wanted to see their father again, unaware of the secrets leering in the Royal Laboratory and the horrors locked away deep inside the True Laboratory of the Underground.