The Answer to Owing Three Thousand Years

My name is Gu Yan. I have died four times and lived four times. There is a 2175-day countdown on my chest and I have lost all memory. But my body remembers three things: A burning tree. A scar on the wrist. An answer owed three thousand years. Now that creditor has come to see me. I have to figure out what I owed him three thousand years ago—— before the countdown reaches zero. Before nothingness swallows everything. Before I made that choice. Burn yourself out or give up everything. Or—— Find what he calls "the third answer."