Formerly: A New And Strange World I got this idea from a comment... Dream (and Nightmare [this wasn't part of the comment, I came up with it myself]) somehow end up in Dreamswap, that's all there is to it.

The bad sanses and the stars were fighting for many years.Now..it's the time to stop these useless battles and make a treaty for the two team. Both of the team wanted this.Nightmare,on the other hand doesn't approve. But one day,Dream found an antitode to turn Nightmare back to normal and live peacefully.However,something terribly went wrong. Did Dream CURE or KILL his brother? Who knows? (■N.B-In this Timeline,Dream only told Science sans that Nightmare is his brother and he has a passive form.No one knows)

A women who loves children dies and is face to face with the decision to reincarnate as nightmare sans if she allows herself to be Karmas chosen child. 'Fgod error belongs to Harrish6'