During the over-one-week stay in the picturesque and verdant city, Chan says, they visited famous historical sites, iconic landmarks and scenic spots, such as the Southern Song Imperial Street, and the Nine Creeks and Eighteen Gullies.

Li adds: "We also spent several days strolling along the West Lake, observing how the light changes from morning to noon and night. This was particularly significant as one of the most highlighted scenes takes place on the lake."

"During the final days of conceiving the script, I suddenly realized — it is simply a love story depicting a man falling in love with a snake-turned-woman and how this unusual couple overcomes difficulties to be together," said Li, with Chan, during an interview with China Daily.

The two directors delved into the preparation work, especially the meticulous research of Song Dynasty painter Zhang Zeduan's masterpiece Qingming Shanghe Tu (Along the River During the Qingming Festival).

The over 5-meter-long scroll features numerous figures, cattle, houses and ships, making it a detailed record of the landscape of the dynasty's capital city of Bianjing (today's Kaifeng in Henan province), and the lives of people from various walks of life. It provided a good reference for the animators to re-create the story's backdrop, set in Lin'an, which is now Hangzhou, Zhejiang province, during the Song Dynasty.