Edition note: An independent English rewriting of the Chinese argument, shaped for English-language readers.

Around 260 BCE, an overlooked Qin prince lives as a hostage in Handan. His name is Yiren. Qin continues attacking Zhao as if his life were worth nothing, and every Qin victory gives the people around him another reason to want him dead.

His mother is unfavored; his father has more than twenty sons. The decision to send him abroad already announces his price.

The merchant who sees a bargain

Lü Buwei asks his father about profit. Farming may yield tenfold; jewels, a hundredfold. What about installing a ruler? The answer is beyond calculation. Lü looks at Yiren and calls him qihuo keju: rare merchandise worth holding.

The word that matters is merchandise. Lü does not first ask whether Yiren would rule well. He identifies an irreplaceable asset—royal blood—then asks why it is undervalued. The prince is cheap because everyone expects him to die.

Lü invests half his fortune in Yiren’s reputation and takes the other half to Qin. There he approaches Lady Huayang, the crown prince’s beloved but childless wife. If she adopts this distant, dependent son, Lü argues, she can turn present favor into security after her husband’s death. Yiren even dresses in Chu fashion and takes the name Zichu to appeal to her origin.

Lü has located two neglected positions and fitted them together. The hostage rises from the back of the succession to become heir.

The third person in the room

At a banquet Yiren sees Lü’s concubine Zhu Ji and asks for her. Lü agrees. The investment is already large; one more gift will bind the future king more closely.

Three people occupy the room, but only two conduct the transaction. Zhu Ji’s beauty, Lady Huayang’s insecurity, and Yiren’s bloodline enter the same ledger because each can be converted into leverage.

Xiang Shaolong watches these events with an advantage no one else possesses. A Hong Kong police officer thrown back from 2001, he knows who will become king, who will become chancellor, and what dynasty must follow. Everyone else thinks he is playing a game. Xiang has read the record of its ending.

An investment that pays

The scheme works. Yiren becomes King Zhuangxiang. Lü becomes chancellor, Marquis Wenxin, and lord of a vast fief. When the king dies three years later, the young heir succeeds and calls Lü his “second father.”

Nothing important in the transaction is fictional. Lü supplies the money, opens the doors, and delivers the future he promised. His danger is more exact than fraud: he can honor every promise while translating every person into value for another plan.

The commodity that was switched

Years later, the grown king eliminates Lao Ai and then moves against Lü. In the television drama’s prison scene, he reveals what Lü never knew: he is not Yiren’s son at all. He is Zhao Pan, an orphan from Zhao placed inside the dead prince Ying Zheng’s identity.

Then he gives Lü poison.

Lü’s greatest investment was secured by the scarcity of bloodline. Its ultimate beneficiary has no share in that blood. The algorithm did not fail because it priced its known inputs badly. Someone changed the person inside the label.

The irony reaches Xiang too. He condemns Lü for treating people as positions, then places Zhao Pan where history requires a ruler. His reasons are warmer and more frightened. To the boy being installed, the shape of the act may be less different than the teacher wishes to believe.

Primary text: TVB’s forty-episode 2001 series A Step into the Past (寻秦记), not Huang Yi’s original novel. Full-series spoilers.