OMFG my mind is blown!
In essence this is a time travel story as Stiles mysteriously awakens 10 years in the past and knows, as well as you and I, that the space/time continuum is not something to be messed with lightly. Inadvertently - definitely inevitably - he is discovered by Derek and the connection is immediate. Will the consequences be dire; is there a chance to change the future?
Something to note is that present day Stiles and Derek are not in a romantic relationship; their friendship just starting to really solidify right before Stiles is wrenched away. What makes this absolutely amazing is all the feels. There is a roller coaster of emotions going on here as Stiles confronts his past and is witness first hand to Derek's life before Kate and the havoc she wrecked on the Hales.
On a side note we know what happened to Derek. We know what he lost. We know how that changed him. This peek at him and his life before the tragedy makes that loss so much more painful, more tragic - visceral in the reality that all he loved was taken away from him in such a cruel manner. It pretty much nails with precision, makes one fully aware in understanding Derek's future grief and resulting pathos - how and why he is who he is.
So yes, this is raw with emotion. The intricacies of the plot are amazingly smart, soulfully extraordinary. The reveal in the resolution once Stiles returns home is absolutely ingenious. The connection between these two transcends time, death, and apparently reality and logical thought. If you want epic romance, an explanation of their otherworldly connection or a definition of their love, then this profound story, to me, explains its amazing existence.Their love was "deeper, stronger, made of something so thick that even the universe itself couldn't break it."
Again. Seriously. Mind. Blown.