when we reach we

Time travel to the past may be impossible. Imagine a bus in motion. You walk from the front to the back and then return to the front. The bus is now far beyond where it was when you got up. You're in a different place now. 

But think of a time in your childhood when you needed something. You needed something and went without. You can send that to yourself now. In other words, change the timeline. Since you no longer exist there. 

Or: four high school students witness a murder, and then live in its consequences. 

Or: Haworth, New Jersey, 07641, United States North America Western Hemisphere Earth our solar system the Milky Way galaxy observable universe multiverse "God”. 2 square miles, streets named after trees and 20th-century-presidents, and the afternoon light is heavy and pure and settles somewhere under your throat like a mouthful of liquid gold. Lots of bikes. Lots of milfs, at least lots of mwbps (moms with biweekly pedicures). And a rapidly expanding mostly Asian minority whom the 3-4-5-generation whites are not unfriendly towards.

Or: a modern young adult science fantasy novel