There’s not much to “the Last Film of the Summer,” Screen Gems’ “The Invitation” — no wit, few frights and not much in the way of thrills, either.

But then, you got that much out of the trailer, didn’t you?

It’s about a beautiful young New York ceramics artist named Evie (Nathalie Emmanuel of “Game of Thrones”) who just lost her second parent, only to discover she’s got relatives over in Jolly Olde.

This much you figured out from the trailer.

Evie’s sassy BFF (Courtney Taylor) agrees with her assessment, looking over the DNA website’s family tree, that they are the “whitest people” ever.

Got that from the trailer.

But her new “cousin,” Oliver (Hugh Skinner) jets over to meet her and begs her to let him fly her back for a big Alexander family wedding.

He’s the one posh twerp “wearing the ascot” in the trailer.

The Gothic decor of New Carfax (Hah!) Manor is her first clue as to what’s afoot. The pale, vulpine looks of the smoldering Lord DeVille (Ha-HAH!), played by Thomas Doherty, are another.

He’s the one with his shirt open to the waist…in the trailer.

Yup, these people are the English Undead, and Evie’s got herself in over her head in a production-designed-to-death British Gothic vampire movie.

Something we all knew that from the trailer.

About the only “spoiler” not in the gives-away-the-movie previews is how slow and tedious Jessica M. Thompson’s film is. Almost nothing of interest happens for well over an hour. The obligatory sexual come-on is preordained to be PG-13. So fixate on how beautiful everybody is, because there’s no clever banter, no chilling “secret,” no fright we don’t see coming or that doesn’t play as a cheap jolt — bargain basement cheap, here.

But you’ve got to reach for reflexive “cheap” scares because everybody watching this knows the formula and has seen what’s coming.

That’s the problem with thrillers that give away the whole damned movie in the trailer.

Rating: PG-13 for terror, violent content, some strong language, sexual content and partial nudity.

Cast: Nathalie Emmanuel, Thomas Doherty, Stephanie Corneliussen, Alana Boden, Sean Pertwee and Hugh Skinner.

Credits: Directed by Jessica M. Thompson, scripted by Blair Butler. A Sony/Screen Gems release.

Running time: 1:44