The coffin jumped to the wall and stopped.
Here, apart from the wall, there was nothing but the wall. There wasn't even a seam, let alone an exit. Just as the Fatty Brother and the Thin Man were wondering, the coffin suddenly flew up, struck the wall a few times, and the sound of rumbling was heard.
The wall, which originally had not a single seam, suddenly cracked open, revealing a large doorway.
The two brothers were dumbfounded. No wonder they had searched for so long without finding a seam; there was indeed a mechanism within the underground palace. No wonder the Elder boasted that they wouldn't find it even in fifty years.
They thought this was the exit and were very excited to finally escape from the enigmatic old man. Without a second thought, they rushed inside, but upon looking up, they were met with four walls again, and their smiles froze.
