A Nanke [prefecture] dream
An grandiose illusion or dream; also refers to how something can suddenly turn to ruin
Negative
而认为房产价格必将在10年或是更久之后恢复上涨的想法也被证明是南柯一梦 | Ér rènwéi fángchǎn jiàgé bì jiāng zài 10 nián huò shì gèng jiǔ zhīhòu huīfù shàngzhǎng de xiǎngfǎ yě bèi zhèngmíng shì nánkēyīmèng
And the belief that housing prices must increase again after ten years or more has also been proven to be nothing more than a dream
[Source]
这些打算在一夜之间化作了南柯一梦 | Zhèxiē dǎsuàn zài yī yè zhījiān huàzuò le nánkēyīmèng
These plans turned to dust overnight
[Source]
To turn to dust
None
The main character's surname is two characters: 淳于 (chún yú)
This story varied slightly between all of the sources that I used
Note that 槐安国 from the story is a fictional country
《南柯太守传》(Nán Kē Tài Shǒu Zhuàn), a work by Táng Dynasty (唐, 618 - 907) official 李公佐 (Lǐ Gōng Zuǒ)
According to legend, 淳于棼 (Chún Yú Fén) was a scholar in the Táng Dynasty (唐, 618 - 907). On his birthday one year, he and some friends were drinking heavily in his courtyard, and he fell into slumber.
When he woke sometime later, he dazedly realized that two envoys had come to invite him to be a guest of the king of 槐安国 (Huái Ān Guó). He accepted the offer, and they started towards 槐安国.
At the king's palace, 淳于棼 met the king. The two of them got along so well that king appointed him to the rank of provincial governor (太守, tài shǒu) in 南柯郡 (Nán Kē Jùn), and he even married off his daughter to him. For twenty years, 淳于棼 lived happily with his wife and his government position. On top of that, he worked very hard and cared deeply for the common people, earning the trust and adoration of the king and commoners alike.
Then, one day, 槐安国 was invaded. The country's initial attempts to repel invaders all failed, and the king ordered 淳于棼 to take charge of the defense.
淳于棼 did his best, but he didn't know anything about warfare, and as a result, he also suffered serious defeats. This angered the king, and 淳于棼 was dismissed from his position.
After the dismissal, 淳于棼 returned to his hometown. When he entered the courtyard of his old home, he was startled to see his body leaned against the wall. He awoke with a start and realized that the past twenty years had been nothing but a dream.