Song of Star Bones: the Last Pioneer

When interstellar human civilization collectively forgot about interstellar navigation technology due to a "cognitive plague" and became "amnesiacs" trapped on their home planet, an exiled archaeologist accidentally deciphered the secret of the "jump engine" from the fragments of the ancient star map. He will lead the last remaining power, rekindle the spark, and launch a lonely expedition toward the depths of the forgotten star sea and the truth about the civilizational disaster.