The Sun Shines Brightly on the Sundial

The sun shines brightly on a dial, what is light and where is it? Before the cataclysm, the world was wrapped in the world of light, and everything boiled with light. After the cataclysm, the world was separated from the light realm, and people lived in the memory of light. However, no one knows that the great catastrophe originated from Lord Long's plan to chase the light. It was not a pursuit, but an expulsion. Shi Lusheng suddenly woke up from his nightmare. There were countless "Is" floating in all possible worlds. So who is the real me?