Time Cut description:

Lucy, a modern high school senior and amateur inventor, accidentally finds a time machine and travels back to 2003, the year her sister was murdered by an unknown serial killer. Now torn between solving the mystery that has undone her parents and her hometown, saving the sister that she never knew, and irreparably altering the future - and her own existence - Lucy must decide how to stop the slasher, save her family, and blend into 2003.