After coming out of the secret tunnel of Ying Clan's castle, Zhang Tie flew around Ying Clan's castle to seek for clues. Pitifully, besides 7 underground secret tunnels leading to different locations, Zhang Tie saw nothing else valuable.
In his lotus-flower eyes, those underground secret tunnels were almost transparent to Zhang Tie. After searching over the 7 secret underground tunnels from the sky, Zhang Tie didn't see anything suspicious.
