(Y/N) had a normal life in the second dimension with her family and friends, and of course, her best friend, William.
One day, William finds a cave with ancient writing in it, but once he repeats the words, he had accidentally summoned and was possessed by a demon and becomes the famously evil, Bill Cipher.
Filled with insanity, Bill wreaked havoc on his hometown, and asked (Y/N) to rule beside him, for the demon fell for (Y/N)'s beauty.
Sadden by her friend's transformation, (Y/N) rejected and fled her town, and soon her whole dimension for Bill, now in anger from her rejection, destroyed their home world.
Y/N is found by the Pine Twins, Mabel and Dipper, and taken in to their home, the infamous Mystery Shack.
But when Bill enters this dimension and finds out his lost love is here as well, he will do anything he can to make her his.