After an accident during an underwater expedition, a modern soul transmigrates into the body of Su Tang, the legitimate daughter of the Chancellor of Great Chu.
At her sixteenth coming-of-age ceremony, the thumb ring sent by Prince Dingbei restores her memories, and she realizes that she has transmigrated.
Her family is at their wits' end over the salt administration. Touching the ring, now hot against her skin, she has a sudden realization: salt may be the key to getting home!
From then on, this sheltered young woman puts aside her embroidery needles and takes up the abacus, heading into the salt business. She establishes a public review council to protect salt workers, reforms profit-sharing to stabilize prices, takes on the old guard in the Salt and Iron Commission, and tears open the corrupt underworld!
The powerful Prince Dingbei, Xiao Chengyu, blocks her way. "Become my princess consort, and I'll give you half the power over salt administration."
Su Tang sneers. "I'll either take it all, or have nothing to do with it!"
Using modern wisdom, she turns Great Chu upside down: salt-tax reform fills the treasury, and border troops get warm clothes and full bellies. She uses the people's support to suppress the old guard, and forces Xiao Chengyu to cooperate by holding him to the regulations.
When affordable salt fills the streets and the people build her a shrine, Su Tang, who had wanted to go home, realizes that this realm has become her responsibility.
Xiao Chengyu slaps down his military tally. "This is your last chance!"
Su Tang checks the salt permits. "We're short by two payments for the winter clothes on the northern frontier. Shall I approve them first?"
Xiao Chengyu: "...Approved."
Xiao Chengyu grips her wrist. "Become my princess consort, and I'll clear every obstacle in your path!"
Su Tang pulls her hand away and flips through the account book. "Your Highness, look. The taxes owed by the Jiangnan salt merchants are enough to pay for three more cavalry units."
After glancing through the accounts, Xiao Chengyu says, "...I'll help you collect them."
Xiao Chengyu blocks the door. "Su Tang, choose: the realm or me!"
Su Tang points out the window. "The people are rushing to buy affordable salt. Your Highness, why not try some first?"
Xiao Chengyu tastes the salt, then silently helps her carry in the newly arrived account books.
