Another summary, found on a subsequent Google search:
The film is about the quest for the “Phantom Tea”. A tea-house proprietor and his daughter go to Taiwan to seek this legendary tea. The movie is being shot in Japan and Taiwan. It is scheduled to be completed by March and might premiere at Cannes Film Festival in May.
it's a love story between two kids from rival tea houses, directed by theater director Wang Ye-ming. And it's possessed of the kind of daunting plot synopsis that tells you everything while leaving you even more confused than when you started:
"In Sung dynasty, a Japanese man named Yagi... couldn't take the badgering from the male black tea tribe and ridiculed that the male black tea was not the best tea in the world; causing the two tribes to challenge each other in a "tea fight." The male black tea tribe massacred the female black tea tribe and burned down the tea farm. A child escaped from the fire and turned into a fire dragon and flew away after drinking a mixture of both male and female black tea. It wasn't until then that the male black tea tribe realized that they had made a big mistake, thus begins the long journey in search of the female black tea."
Well, actually, that's just the legend part of the story (the animated bit). But it does explain why the main characters go to Taiwan.
And from the Nippon Cinema blog of May 2:
The official website for Wang Ye-ming's Taiwan/Japan co-produced movie Tea Fight added a trailer earlier today. The film involves an ancient "tea curse" passed down through generations of the Yagi family. When the wife of a tea shop owner (Teruyuki Kagawa) dies, he believes she was a victim of this curse and decides to shut down his business. His daughter (Erika Toda) takes it upon herself to research the curse on the Internet, and discovers a special tea in Taiwan that can counteract her family's misfortune. Her father follows her, thinking that she's falling into some sort of trap set up by Taiwanese tea makers. Eventually, this all leads to a rematch of a "tea fight" which originally took place nearly 1,000 years ago. Confused? Me too. The trailer won't particularly help matters, but it looks pretty interesting anyway.
By the way, if this movie has been discussed before, my apologies... I hadn't seen any mentions of it anywhere else.
P.S. Edited because apparently I can't spell the word "summary"