Time loop AU where Stiles's stuck in a time loop during the events of the movie up until he finds a way to save Derek.

Is slow moving, the whole process. It takes awhile for Stiles to convince himself that everything is real, that he's not dreaming or stuck in his own head. Even more to actually take the whole 'time loop' angle in consideration. By the time he puts everything together he went through too many time loops, wasted too much time.

Then he began making calls. Initially to seek help from the others, find more information about time loops that he might have missed. It was stated that one was stuck in a time loop when the Universe was trying to fix something, when a wrong takes place. Sometimes a time loop could be willed by someone, forced into existence by someone desperate enough to fix what went wrong. But, as far as Stiles was aware, nothing was wrong. During that period, during all those time loops, no one called him. No one seeked Stiles for help or even made to report any problems to him. But something was wrong and it took for Stiles's calls to get ignored for him to find out.

No one called him and Stiles has been oblivious of everything during all those time loops. When he came to that conclusion Stiles left without any explication and made his way straight to Beacon Hills- just to get in time for Derek's funeral. And Stiles knew in that moment he has to save Derek. That was why he was stuck in that time loop.