C672 The Theory of Forbidden Land
"After opening the stone door, you will reach the end. This is the entrance to the Imperial Forbidden Area, because Prince Long Xuan does not know the way to enter, so do not force yourself. There was an extremely powerful Barrier at the entrance. If one tried to forcibly enter, the Barrier would retaliate. "Prince Long Xuan, remember this." The four Elders warned him before disappearing