Kaze no Na wa Amnesia

The Apocalypse didn't come with a BANG. Silently, the amnesia wind swept away all of mankind's knowledge. Thousands of years of human civilization vanished overnight as people forgot how to use the tools of modern civilization - who they were - how to speak - everything. Technology decayed as mankind was instantly reduced to level of cavemen.
Now, two years later, a young man explores a nation reduced to barbarism - America. Miraculously re-educated after the cataclysm, he is accompanied by a young woman- somehow spared the obliterating effects of the amnesia wind. Pursued by a relentless killing machine, they search for those responsible for stealing their memories.