/lit/ - Literature

A boy falls in love with a girl. Unable to confess, he stalks her and learns she is convinced she can capture a signal from either out space or the afterlife with her jury-rigged ham radio. He builds a device of his own and begins creating phony signals from a post apocalyptic future, claiming he seeks to undo the downfall of mankind. They cannot communicate directly due to the time difference, but if she keeps sending her signals and dating them accurately, he can send responses to her at appropriate times.
A correspondence is born. He continues to paint and ever crueler and bleaker picture of the future and lamenting lost love, hoping she will cherish the precious opportunities in her life.
Due to time dilation his voice is unrecognizable, so when the two meet "by accident" irl she doesn't recognize him. As the man from the future he continues hid correspondence, speaking of how he misses grass or beaches, while in the present he takes her out to such activities. As per his request, she keeps her contact with the future a secret until they can figure out a way to avert disaster.