During the Shaoxing era of the Southern Song, crab inspector Liu Bi is ordered to Wujiang to collect tribute crabs. A sudden earthquake swallows up his companions and their crab boats, leaving only a handful of survivors.
Meanwhile, northern rebels hiding around Lin'an reveal themselves. They massacre civilians along the river and force Liu Bi to pilot a boat through the checkpoints, hoping to exploit his position as a crab inspector to infiltrate the Court of Imperial Sacrifices and reach the Mid-Autumn Festival celebrations, where they plan to seize the emperor and issue commands to the realm.
In the midst of it all, Liu Bi suddenly realizes that the command pennant shaping the fate of the realm has somehow fallen into his hands.
Will he remain in the south, enjoying an age of song and dance, or reclaim the lost lands and return the capital to its rightful place? See how this humble crab inspector breaks through one crisis after another, survives against all odds, and saves the Great Song from ruin!
