To her, this thing was nothing but a piece of junk, yet now she called it a treasure. The liquid metal monster had no choice and hesitated for a moment before saying, “I’ll render another service, then please give it to me.”

“Speak,” she knew this creature was hiding something. How could a River God who had concealed its true identity for many years not have stories to tell?

“The letter from old Cao that you just obtained has another secret.”

“Oh? Invisible writing?” Her interest was piqued. “But Yun Ya already examined it and found no traces of chemicals.”

“Would ordinary chemicals work?” The liquid metal monster giggled. “Watch me.”

Feng Miaojun spread the letter flat on the table, and the liquid metal monster jumped onto it, transforming into its original form and spreading mercury all over the paper. Feng Miaojun then placed the letter on oiled paper and heated it slightly. Sure enough, dark red characters appeared on the paper’s surface.

But when the liquid metal moved away, the writing quickly disappeared.

“This kind of chemical only reacts with metal, and requires heating.” The liquid metal monster said proudly. “Old Cao is already dead. If I don’t tell you, nobody will know.”

Feng Miaojun gave it a look: “If that’s the case, who was Cao Budao writing this letter for?”

The liquid metal monster was suddenly at a loss for words. Indeed, people who drew the divination stick would only see the visible text, while the invisible writing would only appear under special conditions. So who exactly did Cao Budao want to reveal the true contents of the letter to?

The crucial point was, that people who couldn’t catch the liquid metal monster wouldn’t be able to see the letter’s secret at all.

Feng Miaojun knew this question couldn’t be answered for now. She adjusted the lamp wick and settled down to read the letter.

She had found it strange earlier—why would just a few small lines of text be written on such a large piece of paper, leaving so much space? Cao Budao didn’t seem like a careless or wasteful person.

Now she understood—there was so much invisible text on the letter.

As she read further, her expression grew increasingly solemn.

This letter, like before, was not a divination verse but Cao Budao’s account.

In the lines, he recorded a secret he never shared with outsiders.

“In my youth, I was arrogant, disregarding the principles of heaven’s way and unwilling to accept the suffering in this world. I wished to help people pursue benefits and avoid harm, to transform misfortune into fortune…”

Cao Budao narrated in his letter that he attained enlightenment at a young age and was extremely prideful. Unable to bear witnessing the various sufferings in the world, he often revealed heaven’s secrets with a single word, helping people resolve disasters and difficulties. Because of this, his reputation soared, and cultivators would travel thousands of miles just to seek a single divination from him.

At that time, Cao Budao was confident in his profound divination skills and neither feared nor believed that heaven’s way could do anything to him. It wasn’t until he grew older and his temperament became more steady that he reflected on his youthful arrogance as excessive and began to fear heaven’s punishment.

Sure enough, retribution came.

Cao Budao’s wife suddenly hemorrhaged during childbirth. Although she eventually delivered a son and the bleeding was barely stopped, her health deteriorated from that point on. Cao Budao took her to seek immortal physicians and gave her all kinds of precious elixirs, but the answer he received was that she had exhausted her life force and was beyond saving.

When people are injured or seriously ill, as long as their life force isn’t extinguished, skilled physicians with various rare medicines can usually save them. But if the source is depleted, then the human body is like a small pool without a spring—it will eventually evaporate completely under the scorching sun.

Deeply in love with his wife, Cao Budao naturally couldn’t accept this outcome. But after consulting many worldly physicians, they all proved helpless. He also used divine techniques to perform countless divinations, hoping to find that slender thread of hope for survival.

The answer was: that there was none.

Watching his wife gradually waste away, approaching death, Cao Budao, in his boundless grief, suddenly conceived a bold idea:

If there was no path to life, what about a path to death?

Since his wife could no longer live, then as a second-best option, why not keep her soul by his side?

He shared this thought with his wife, who gladly agreed.

Theirs was love as inseparable as mandarin ducks, unwavering even unto death.

With Cao Budao’s abilities, capturing and settling his wife’s soul after death wasn’t difficult. The problem was that after death, souls were supposed to return to the netherworld, otherwise ghost officials would come to arrest them after the appointed time.

These ghost officials were not the pushover minor characters from supernatural fiction. The soul-binding chains they wielded represented the laws of heaven and earth, something human power simply couldn’t resist. Moreover, in a world where spiritual energy was declining, cultivators’ powers were becoming increasingly weak, making victory against them even more impossible.

Cao Budao knew that before this era, countless wandering ghosts had roamed this world, and immortals even kept powerful ghost creatures as pets. But those were bygone matters. After that terrifying celestial anomaly, the power of reincarnation was strengthened, and every soul whose physical body had died was forcibly taken to the Yellow Springs unless it had been completely shattered.

Combined with another little-known reason, very few wandering souls remained in the world. Even those that did mostly possessed the cultivation of over a thousand years.

Cao Budao’s plan to hide his wife’s soul at this time was unrealistic.

He considered various ideas, but none withstood scrutiny.

Just when he was about to tear his hair out in frustration, on a stormy night, someone suddenly appeared at his door.

The appearance of this person wasn’t important, because Cao Budao saw through its essence at a glance:

A Celestial Demon.

Well-versed in classics and histories, he naturally knew what role Celestial Demons had played over the past thousand years, so he maintained high vigilance and wanted to turn it away.

However, the Celestial Demon’s straightforward question made him change his mind: “Do you want to keep your wife?”

Want to? Of course, he wanted to—he dreamed of it!

The solution offered by the Celestial Demon was peculiar: a swap.

The netherworld officials would take a dead soul back, then… let them do their job, but what they would take back wouldn’t be Cao Budao’s wife, but another soul.

As long as this soul could successfully substitute for Cao Budao’s wife’s blessings and sins, it could enter the cycle of reincarnation in her place. This way, Cao Budao’s wife could remain in the mortal world, and the netherworld would no longer trouble them.

In simple terms, the core of this method could be summarized in four words:

Fraudulent impersonation.

Cao Budao was greatly surprised, but after pondering for two days, he found the method increasingly feasible!

Exams had stand-ins, prisons had substitutes, and condemned criminals had replacements—why couldn’t reincarnation be substituted? However, what kept him doubtful was that the Celestial Demon hadn’t proposed any exchange conditions.

In other words, it was voluntarily helping him accomplish this, asking for nothing in return.

This was something Cao Budao couldn’t trust under any circumstances. Although Celestial Demons had quite good reputations, always fulfilling what they promised, almost no one who made deals with them ended up with a good outcome.

Over the next few days, he tossed and turned, carefully contemplating, but couldn’t divine the Celestial Demon’s intentions.

Then, he ran out of time.

His wife’s life was fading like a lamp running out of oil, about to exhale her last breath.

At the crossroads of life and death, he couldn’t refuse any request from the Celestial Demon, let alone when the other party was offering to help for free.