Fan CastingThe Flash: Into the Dark Side

The movie opens as the Rogues plan to blow up the Flash Museum. Just as Cold is about to activate the bombs a streak goes past him and takes the detonator. We see Barry Allen and Wally West arrive just as the streak stops and reveals itself as a huge armored speedster who tells them his name is Savitar. Barry goes for the detonator but Savitar activates it and Wally stops time. Just then Savitar starts moving and grabs Wally throwing him into a time portal just before killing Barry. Throughout the movie Wally tries to navigate the past after being thrown 10 years into the past and meets a younger Jay Garrick who helps Wally try and find out who Savitar is and what he wants. The movie ends with Wally and Jay using the cosmic treadmill they built to go to the future and trap Savitar in the Speed-Force. Before they close the portal and trap him Savitar reveals that he is the future Barry from another universe who after gaining speed hunted the man who killed his mother. He managed to find the man in another timeline and so he used all of his speed to travel to the future. After murdering him he corrupted himself and the Speed-Force of his universe. After that his universe fell apart and so he came to Earth 1 to replace it's Barry. Wally closes the portal and returns to the moment where the detonator goes off and stops Savitar before he does it. We see Savitar in the Speed-Force as he is killed by Black Flash causing the Savitar in the present to fade away.