Because of relativity, you can have locations A and B in spacetime and a frame of reference such that A happens before B and a different frame such that B happens before A.
So, if you're at A, you can travel faster than the speed of light and arrive before B happens. Then, after B happens, you can travel back to before A happens.
So, if you're at A, you can travel faster than the speed of light and arrive before B happens. Then, after B happens, you can travel back to before A happens.