This Song Inspires A Whole Story In My Brain

I have the coolest story about two mutant sisters. A speedster and a time traveler who can't time travel. One is damaged and has trauma in her past as a mutant agent for the Government where her entire strike team was killed and she was scarred. Her little sister is now at her same facility and she is loved by everyone while the older sister is hated for how she lost her team a decade in the past. The little sister can manipulate chronal particles to change the flow of time in a localized area, say a room, but she cannot time travel per say. She can live between the seconds in her immediate reality. Together with a little help from the sister bond that can even survive pettiness and jealousy to rewrite history and save a group of heroes from dying in the past.