On the day of the Spring Equinox, the crowds in front of Songhe Tower were bustling. Tang Ren stood on tiptoe and looked at the storyteller on the stage. The crab roe soup bun in his hand dripped with oil, which fell on Su Chen's newly changed Hangzhou silk gown.

"It's dead!" Tang Ren hurriedly wiped it with his sleeve, but Su Chen held his wrist. The oil stain on the fabric slowly spread out, revealing a vague landscape pattern. "This silk... has it been soaked in alum water?"

The wooden door in the hall suddenly rang. The storyteller was just telling the story of "The Five Gallants" when suddenly there was a "click". Everyone looked up and saw the carved wooden window of the elegant room in the upper floor collapsed. The Tea Master was lying beside the window with a half-broken bamboo tea spoon stuck in his throat.

When the coroner at the prefectural government was performing an autopsy, Qin Feng stared at the murder weapon in a trance: "The handle of the teaspoon is engraved with the name 'Gongchun'." Su Chen wrapped the blood-stained bamboo piece in a handkerchief and looked at it carefully against the light: "It is an imitation of the Gongchun teapot of the Ming Dynasty, but the bamboo material is Xiangfei bamboo."

The man followed the source of the tea spoon and found "Taoranju". The shopkeeper wiped his sweat and explained: "I just received a set of purple clay teapots last month, a total of ten pieces..." Tang Ren suddenly pointed at the antique shelf: "Why is the corner of this tea boat missing?"

Su Chen turned the broken lotus leaf-shaped tea boat, and the secret compartment at the bottom popped open, revealing a yellowed tea ticket. On the front of the ticket was printed "Biluochun, the tenth year of Guangxu", and on the back was written in small regular script: "At 5 pm, Tiger Hill Sword Test".

The moss marks on the sword were still wet, and Qin Feng touched the indentations on the surface: "This, this is newly cut!" Tang Ren was approaching, and suddenly his feet slipped. When he picked up the dead branches in the pond, he found that the branches were entangled with golden threads - exactly the same as the materials at the scene of the Songhe Building murder.

Su Chen scooped up water and splashed it on the wall. The water seeped into the cracks and revealed a tooth-marked imprint. Tang Ren took out the purple clay fragments he picked up at Taoranju to compare, and the tooth shape matched perfectly: "Has this murder weapon ever hit my head?"

The sound of night watchmen was heard in the twilight, and Qin Feng suddenly pointed at the water surface: "Reflection!" The shadow of the tower in the pool was twisted into the shape of the Big Dipper, and the position of the seventh star was right opposite the Shenggong podium.

The moonlight illuminated the new mark of the "nodding" character. Tang Ren held up the fold and read: "In the month of Bingshen year..." The words stopped. Su Chen's fingertips touched the surface and felt a concave dot at the horizontal stroke of the character "申": "It's the '七' in Suzhou code."

Qin Feng suddenly knocked open the merit stele behind the podium, and under the stele was half a piece of blood-stained Xiangfei bamboo. After splicing, a code message appeared in the light: "At 12:00 a.m., the moon is shining on the lake."

After the fifth watch gong sounded, the people hired a boat to rush to the lake. When the boat passed the Xingchun Bridge, Tang Ren suddenly pointed at the bridge hole and said, "Look! Isn't that..."

Eighteen bridge arches reflected eighteen round moons, but the bow of the boat suddenly turned. The old boatman touched the water with a bamboo pole: "Sir, please be careful, this waterway was changed half a month ago!" Su Chen unfolded the old river map, and the place where the waterway was changed looked like a Q.

Tang Ren picked up a piece of wet silk while he was vomiting while holding onto the boat. Qin Feng used a silver hairpin to pick up the gold thread, revealing a blood-grooved tea knife. Su Chen sniffed the blade: "It smells like Biluochun."

As the boat passed the Treasure Belt Bridge, dozens of black shadows emerged from the water. Tang Ren grabbed the oar and slapped it, but was startled to see a shattered moon all over the lake - it turned out to be dozens of buoys with silver mirrors tied to them.

In the morning mist, Su Chen turned the bronze mirror on the buoy. Where the reflections converged, a bloody handprint was clearly visible on the willow tree on the shore. Tang Ren climbed up the tree to get the oil-paper package, which contained half a copy of "Yang Xian Ming Hu Xi" with a pawn ticket between the pages.

"The tenth year of the reign of Emperor Guangxu...Pawn item: a red clay pear-shaped pot..." Qin Feng stopped reading halfway, "The pawnshop is the Yongchang Pawnshop that was sealed the day before yesterday!"

When he returned to the ruins of Yongchang, he heard a strange noise coming from the charred counter. Tang Ren pried open the floor tiles and found dozens of purple clay pots neatly stacked in a secret compartment, each with the birthdate of the wrongfully deceased engraved on its bottom.

The dragon kiln at the foot of Shushan Mountain was emitting green smoke. Su Chen held a piece of broken clay and pondered: "This red clay is mixed with bone powder." The kiln worker suddenly knelt down and cried: "Master Li fell into the kiln in Yueyue, and the human face pot fired was... taken away by the shopkeeper!"

Qin Feng found half of a contract in the waste pile, and the buyer's signature turned out to be the owner of Songhe Building. When Tang Ren kicked open the door of the warehouse, more than a dozen pottery jars suddenly exploded, and the bloody account book was wrapped in the flying porcelain pieces.

"The 20th day of the month of the Bingshen year..." Su Chen turned to the last page and his pupils shrank suddenly - it was exactly the morning of tomorrow!

Amid the sound of the Buddhist bell, a man lay in the reeds beside the Maple Bridge. A pleasure boat floated on the river, with a red clay pot on the incense table at the bow. The owner of Songhe Tower was about to burn incense when he heard a sound of breaking air - the purple clay fragments thrown by Su Chen smashed the pot, and the ashes were scattered by the wind.

"This is Master Li's..." The kiln worker rushed out from the bottom of the cabin, holding the kiln iron kettle. The painting boat suddenly tilted, and dozens of pottery jars floated down the water, each with a bloody Q engraved on it.

When the prefectural government officials were collecting the bones, they found a skeleton at the bottom of the river. The skeleton was wrapped in a jade ring with the word "Yongchang" engraved on the inside - it was the pawnshop owner Lao Chaofeng who had disappeared ten years ago.

The late spring drizzle wet the green board. Tang Ren chewed the plum blossom cake and mumbled, "Is it revenge?" Su Chen put away the oil-paper umbrella and walked into the teahouse. The newly placed red clay pot on the counter suddenly exploded. Qin Feng picked up a note from the fragments:

"Heaven's work is a gift, blood debt must be repaid with blood."

The copper bells on the eaves rang again, and the storyteller was startled by the wooden clapping in the hall. This time, he was talking about an old story about an apprentice sinking a kiln ten years ago.