What's the main theme of the Hong Kong chapter (theatrical version) of the magic card girl cherry blossom?

On the way to KINOMOTO SAKURA to buy a notebook, I got a special reward-a trip to Hong Kong. I'm really lucky for ordinary people. Woody Sakura, who was overjoyed, immediately discussed with her family after returning to China, resulting in a four-person tour group of Woody Sakura, Zhishi, Touya and Shantu. After the last person moved to Hong Kong, Woody Sakura suddenly felt a strange smell. After chasing the smell, he met Xiao Lang. The world is really small. Seeing Sakura Woody after the victim, Xiao Lang decided to invite everyone to his home. Mother wolf is really authoritative. Woody Sakura, who lives in Little Wolf's house, had a strange dream. In the dream, she was dragged into the water by a woman she didn't know. After waking up from a nightmare, Little Wolf's mother came and made divination for Woody Sakura, telling Woody Sakura that its powerful power can easily attract magic, which made Woody Sakura very concerned. Later, Little Wolf's mother warned Woody Sakura to be careful with water and sent Little Wolf to protect Woody Sakura. That's prescient. Who is the woman in sleep? Why did she bring woody cherry to Hong Kong by magic? What happened to Coolidge's "water is a flowing thing"? Let's find the answer by ourselves in the plot.