Fic Title: Changing Phases
Word count: 21k
Decades into a new era and space is no longer the world's new frontier. But after otherworldly aggressors prove too much of a threat, the Earth shuts itself away, raising an invisible wall between it and the universe at large.
Jared and Jensen are both products of their time, and they fight to make their mark in the Earth's military forces. But they learn soon enough that the greatest threat of all might not be the one up there in the sky.
Link to fic: livejournal / AO3