Four people. One letter. An ocean between them.

To send a letter home from Bangkok in the 1950s, an overseas Chinese laborer needed four people: himself, a scribe to put his words on paper, a reader to decode it at the destination and the person waiting to hear it read aloud. Lan Hongchun built a $291 million film around that chain – and everything that could go wrong inside it.

“Dear You,” which closed the 25th New York Asian Film Festival, is a RMB14 million ($2.1 million) dialect picture spoken almost entirely in Teochew, rooted in a form of correspondence most audiences under 50 couldn’t identify. It has become the second-highest-grossing film in China this year, after “Pegasus 3,” earning $285 million locally with a further $6 million from its first wave of international markets.

Speaking to Variety at the festival, Lan — who directed, wrote and edited the film — does the math out loud. His best-case projection going in was somewhere between RMB100 million ($14.8 million) and RMB200 million ($29.5 million) at the China box office. “It is 10 times more than what we have expected,” he says. “Now we are looking at RMB2 billion ($295.5 million), and it’s still growing.”

He attributes the unpredictability in part to something shifting in the audience itself. “The film market and the box office in recent years seems to be a little bit more unpredictable,” he says. “I do think that maybe it has something to do with audience aesthetics — the films they like seems to be evolving, and it is hard to really predict what they truly enjoy.”