After the Sun Dies

Master said that the sun is going to die. I think he is crazy. The day after he told me everything, he left a letter and left. He said that he was going to find the nine suns that were sealed back then, that is, the nine golden crows. I think he is joking with me. But one month after Master left, the sun really died and the earth fell into darkness. Intention: Who is carrying the burden forward?