Time Cut (Netflix)

Lucy (Madison Bailey) lives in the shadow of her teenage sister, Summer (Antonia Gentry), who was murdered by a serial killer in 2003, years before Lucy was born. It's 20 years later, and her parents are still in deep mourning for Summer.

When Lucy accidentally time-travels to 2003, days before Summer's murder, she makes a new friend (Griffin Gluck) when she steps in to save him from bullies. Eventually, she also meets Summer and her high school friends. Worried about destroying the future if she alters the past, Lucy tries to save the first two teens from the killer, then has to make a big decision. Should she try to save the sister she never knew, even if it means she'll never be born?