It's the morning of Lantern Festival more than 1,000 years ago, when the Tang Dynasty (618-907) was in its prime. The then capital Chang'an, today's Xi'an, Shaanxi province, awakens and stirs as its residents anticipate the evening's celebrations.

Lanterns are hung, market stalls are opened, vendors shout to attract customers, and the crowd gathers as street performers showcase ethereal traditional dances or awe-inspiring stunts. A wonderful night is ahead, with the city illuminated by thousands of lanterns, and festivities begin.

Little does the jubilant crowd know that an enemy attack looms — explosives are hidden around the city and soon detonate as the night quiets down. Li Bi, chief of the intelligence bureau, turns to Zhang Xiaojing, a former soldier and security official now under a death sentence, to save the day.

It is The Longest Day in Chang'an, a musical adaptation of writer Ma Boyong's eponymous suspense novel. The production premiered in Beijing on Feb 14, staging five performances over three days, and will perform in Shanghai from March 13 to 23.

The novel depicts a series of intertwining events that unravels the conspiracy and averts the crisis within 24 hours, or 12 shichen (a term referring to a two-hour time period in the traditional Chinese timekeeping system).

Despite the single-day format, the two-volume novel comprises around 500,000 Chinese characters. Condensing it into a 210-minute stage production proved challenging, says Hu Xiaoqing, the production's director.

"After each run-through, we made adjustments or deleted scenes, but the story has a lot of foreshadowing necessaries for the audience's comprehension," Hu says.

"Other things we felt obliged to keep include an introduction to the architecture, the imperial government organization, and some unique Chinese language expressions. It is important to convey Chinese cultural elements in addition to telling a story."

One of the novel's captivating aspects is its depiction of the capital, a symbol of the Tang Dynasty's prosperity and opulence. Enclosed by city walls, Chang'an adopted a meticulous urban design, divided neatly into 108 blocks with designated functions.

In the stage design, the crew strives to present the city's outline. While it is impossible to fully demonstrate its grandeur, the stage floor adopts a checkerboard design to convey the concept, with three movable watchtowers indicating different locations.

The opening song Chang'an and the first song of Act II Zhengyue Shiwu (referring to the date of Lantern Festival) are designed to give the audience an immediate impression of the city.

"The audience feels at the beginning Chang'an's lively prosperity, where people live in peace and joy despite the story's lurking crisis. The start of Act II presents a lighting ceremony for Lantern Festival, incorporating dance, folk music, acrobatics and martial arts," Hu says.

"We hope to immerse the audience in a cultural atmosphere, with various artistic techniques and rich colors that portray traditional aesthetics."

An Dong, the musical's composer and the director of the Shanghai Conservatory of Music's musical theater major, says when writing the music, he tried to reflect the essence of Chang'an — a vibrant, multicultural metropolis, the inhabitants of which come from not only different ethnic groups but from around the world.

"Instead of strictly using traditional Chinese music, I adopted a fusion of worldwide cultural influences that mirrors the capital's diverse nature. It is also necessary to represent the unique musical expressions of the Tang Dynasty," An says.

While composing music that appeals to younger audiences within the framework of contemporary musical theater, he sticks to the principle of not being just a collection of catchy songs.

"This musical carries a lot of weight, and the songs must serve the storyline, fit the characters and match the profound historical ambience," he says.

The production features folk musicians onstage, who blend into the scenes with their Tang Dynasty attire and pipa (a four-stringed Chinese lute), bamboo flute and drum performances.

An agglomeration of ethnic and folk music styles is adopted. Qinqiang Opera, a traditional opera style from Shaanxi, represents the local cultural flavor. A particular song written and performed in the Yi ethnic group language represents ethnic diversity. Persian and Arabic music styles reflect ancient Silk Road economic and cultural exchanges, and Western operatic style matches the story's solemn themes.

"I thought highly of the project's subject. First, it is a captivating story with the potential of being adored globally. Second, it speaks of the love for the people and one's homeland, and the determination and resilience to protect them, which are shared values worldwide," An adds.

In line with the Tang Dynasty's diversity, the story includes a foreign character, Gelao, the head of an underground society.

The role stars French singer and actor Laurent Ban, beloved by many Chinese musical fans for his performance in Mozart, l'opera rock.

Although having no formal Chinese background, he speaks and sings in Mandarin in the musical, and even performs a song adopting the Qinqiang Opera style.

The idea of embracing a new challenge, to embody an original character in a language foreign to him, was one reason why he accepted this role, along with the production's historical depth.

"I love China for the richness of its history, like France. I enjoy diving into the golden age of Chinese history through the Tang Dynasty, and I also love that the story is set in Chang'an — the ancient name of Xi'an, a city I adore," Ban says.

To prepare for the role, he worked with the crew members, practicing intently to grasp the pronunciation, tone and rhythm of the Chinese language, honing his acting and singing skills, and fully realizing his interpretation of the character.

"Each scene requires extreme concentration and leaves me feeling drained as if I had run a marathon," he says.

Even now, he continues to work on his pronunciation and tones, feeling there is room for improvement. Still, the joy of bringing the story to life amid a supportive team was immense.

"I'm not only excited to play my character but also to watch my colleagues perform onstage. Everyone gives 1,000 percent — the dancers, singers, actors and everybody involved — it's truly exceptional," he adds.