The story follows the legendary Tianzhan Sword (the "Sky-Sunder Sword") and three young heroes who set out to find it. Wei Gui survives the massacre of his family as a child, but the shock leaves him with no memory. The only clue to his past is the Tianzhan Sword, a name etched in his mind. While searching for the sword's shattered blade pieces, he teams up with Lei Ling Ze, a hot-blooded Lei Clan disciple determined to be No. 1 under heaven, and Hua Xiao Hua, a sharp, quirky girl who deals in jianghu secrets. As they hunt for the sword and try to save lives along the way, they clash with Tianwai Tian, a ruthless dark sect bent on claiming Tianzhan for itself. Through every setback and showdown, the trio holds the line with grit, loyalty, and a code they refuse to break: trust your friends, protect the weak without showing off, stand by courage and righteousness, and keep the world in your heart. And the thrilling story leaves one message loud and clear: being "number one under heaven" isn’t about the sharpest blade, but about the strongest sense of justice. (Source: Youku.TV)
