Now imagine your time as a vast ocean. Your action - throwing the stone into it - will create ripples. But those ripples, however huge at first, will lessen as they spread throughout the waters of time. Until, at the oceans edge, more likely before,, there is no evidence they ever existed.
Understand, your time is a vast ocean, acted on by forces much stronger than those of these physical dimensions. Your actions and consequences are comparatively nothing.
We have been here, studied you, many times in what you call your past and future.
Tracey laughed. "Then you can take us back...?"