Desperate Echo (Sans x Reader)

Everything was great for (y/n), especially being able to have made many monster friends since they came from mount ebbot about a year ago. One of the best days so far for you was going to the gym for your brother, and meeting Sans, who is also there for his brother. The rest after that, was great except..... Someone in (y/n)'s family has kept something from her for years. And it might just be the end for her.