Film in 100 words (well 170 but whatever)

 The core unrefined idea of our film is that it involves our protagonist gains the ability to travel in time, but only after experiencing great emotional anguish following the death of her best friend, and she time travels back to the moment her friend died in a tragic accident to attempt to save her friend and change the past. However her efforts are in vain, and as the protagonist saves her friend from the accident another event occurs and her friend perishes again, in an effort to stop this the protagonist keeps going back in time to try again and each time she fails to save her friend. Until it is revealed to her in some way that her friend had committed a horrible act of betrayal to the protagonist, and the protagonist fueled by hatred uses her time travel ability to kill the very friend she has been so desperately trying to save, and it is revealed that the whole time it has been the protagonist has been the one undoing the protagonists efforts to save her friend.