Long ago four races over Earth : Monsters,Humans, Ponies and Others . One day a magical discharge accident involing a pregnant Queen Anna,Alphys' parents ,Undyne's parents, Gaster and a few humans when the leaders got there .

The king of humans saw the monsters then humans , he turned the king of monsters and start blaming Gaster for magical discharge ,then said the skeleton boss monsters to send away.

Suddenly the king said to the king of monsters "this is means war", the king of monsters said "This is not the answer " and the human king let them off with a warning but he said the skeleton boss monsters need to go into hiding.

Gaster sighed sadly and said "Can I go to my friend's house?" to his king . King Andy said "Yes" to Gaster and he go to the Hernandez's house to tell his friend Bell , what happened when he got there Bell was waiting for him.

Time skip

One day the prince of the monsters was born , his name is Asgore and he had a good live while Gaster and Bell feel in love and start dating and many years later they got married and moved into a big house next to a river. Bell become sick and Gaster was panicking about his wife's sudden sickness. Bell asked Gaster to call their doctor. Their doctor was named Ruby Rabbit.

Ruby got to the Font family's house to see Bell ,she knocked on the door and Gaster answered it. After some tests ,she finds out what wrong with Bell.

Ruby said Bell is pregnant and Gaster fainted. Months later a skeleton boss monster was born , his name is Comic Sans Serif Font but Sans for short. His grandparents visit them all of the time and they was proud.

Time skip - year later

One year later the princess was born , her name is Toriel Dreemurr , Asgore saw his little sister for the first time and he wants to keep her safe all costs. Toriel grow into a kind and generous princess , one day Toriel and Sans meet each other . Through time they got a crush on each other.

Time skip - Papyrus and Asriel was born.

Year later the war between Humans and Monsters start but the ponies tried to make them stop buy it did not work. Lots of lives was lost. The humans was victorious and sealed the monsters into a meadow.

Time skip
A human named Rose feel into the meadow and saw alot of monsters . She runs away from them. She come across the Font family , she got scared and start attaching out of self-defense. Bell become angry with the human and started using her magic. Rose started throwing knives at them and one of the knives hit Bell , killing her, Sans saw it happen and scarring him for life. Papyrus did not know what was going on.

Time skip good ending
Frisk left her abused father with all of her stuff in her backpack to find her sister Chara who went to the meadow. She heard the stories of humans going there who don't come back. She fell in the meadow, she saw a few flowers in there. On her trip ,she meet alot of monsters who become her friends. Flowey catch everyone and she saved them. Toriel become a mother to her and Sans at first was scary of her but through time , he saw that she did not want to hurt him and he became a father to her. The barrier was broken and they meet alot of friends but they want to stay in the meadow and recalled it , Rosebud village.