"You know something about radiation, don't you?"
It was perhaps the last thing that Celestia, protégé of Queen Harmony, was expecting her mentor to ask. Having a cutie mark related to the sun didn't prepare her for an expedition to the ocean floor to investigate a strange signal and then decide if the source should be salvaged. In the depths, Celestia makes a discovery that could change ponykind forever and she struggles with the implications as the full weight of responsibility begins to press down. Equestria's future will depend on her decision.

Now with reading!
And another reading!