The customs officer in Tokyo asks her, “Purpose of your visit?”

And Sweetpea (Dree Hemingway) is perfectly blunt in reply.

“I came here to break up with my boyfriend.”

But her boyfriend is a mercurial, fragile rock star. He’s shooting a video in a famous and mysterious Japanese forest, and he has other ideas. And since Sweetpea never saw the Natalie Dormer thriller “The Forest,” she has no idea what she’s in for.

Everybody in “The People Garden” goes out of his or her way not to name the location of this music video shoot. It’s Aokigahara, Japan’s “Suicide Forest” on the slopes of Mount Fuji. It’s where the despondent go to wander off, find an unoccupied tree, and hang themselves.

The only reason not to name the place is the earlier movie about this spooky, real-world oddity. A lot of people saw the earlier film, and naming the forest would have been admitting another movie beat you to the subject and amounted to a final nail in the coffin of this drab, dreary thriller.

Hemingway, daughter of Mariel, great grand-daughter of Ernest, is a model turned actress and a drab screen presence with no hint of spark or any other reason a rock star would be attracted to her or despondent over her ditching him.

Given an idiotic character name and playing almost every moment with a kind of resigned puzzlement, Hemingway sucks the oxygen right out of this mystery.

Because that’s what it is supposed to be. Sweetpea is left at the airport, and then ditched by the driver, Mak (Jai West) who is not supposed to “let her out of your sight.” He leaves her at the entrance to the woods with a crude map to the filming location, and police tape to stretch out between the trees to keep her from getting lost.

She finds the place — no thanks to Mak — and takes in the dullest, most unhurried video shoot in Japanese history. James Le Gros is the director, Pamela Anderson the 50ish model hired as eye-candy. Yes, she strips.

Jamie, the rock star? He’s gone missing. And no one seems that upset about it.

Did he flee before Sweetpea’s arrival to avoid being dumped? Did he get lost? Is he on strike? Or did he sneak out to kill himself in the “Suicide Forest” no one mentions by name?

The mystery in actress-turned-writer/director Nadia Litz’s (“Big Muddy”) narrative is no mystery at all if you’ve seen “The Forest.” Even if you haven’t, the funereal pace and willfully cryptic way everyone treats Sweetpea (Must be the name.) drives any interest out of the story before its big reveals are revealed to be not big at all.

The setting itself — a hardwood forest in Canada — is damp and grey and properly creepy. But “The People Garden” guards its feeble secrets so well audience ennui sets in, as it always does when we’re way ahead of where a movie is taking us.

And Hemingway? There are hints of her mother’s mousie voice in lines delivered through the same locked jaws Mariel was famous for, but no trace of mom’s empathetic charisma. There must be more suitable ways for Dree to capitalize on her famous  surname, because acting doesn’t seem to be her calling.

MPAA Rating: unrated, nudity, suicide

Cast: Dree Hemingway, Jai West, Pamela Anderson, James Le Gros
Credits: Written and directed by Nadia Litz. A FilmBuff release.

Running time: 1:22