“Rogue One: A Star Wars Story” takes place between Episodes III and IV of the official “Star Wars” series. It answers the question of how Princess Leia came to be in possession of the plans for the Death Star at the beginning of Episode IV. It also answers the question of why the Death Star was built with a convenient “Destroy Entire Death Star” feature. So it serves to fill in a few blanks. And yet “Rogue One” feels like an entirely useless movie. Not only is it hard to get invested in aspects of the story that we know won’t continue, but it quickly becomes apparent that those aspects aren’t worth continuing anyway.

Felicity Jones stars as Jyn Erso, the daughter of engineer Gelen Erso (Mads Mikkelsen), who is being forced to work on the Death Star by the evil Director Krennic (Ben Mendelsohn) of the Empire (when will movie villains realize that it’s a bad idea to have dissenters build their superweapons?). She’s recruited by the Rebels to go on a mission to track down her father, who they plan to assassinate. She’s accompanied by Rebel officer Cassian Andor (Diego Luna) and his wisecracking robot K-2SO (Alan Tudyk). First she has to track down old family friend Saw Gerrera (Forrest Whitaker) and while on his planet, the team adds blind warrior Chirrut Imwe (Donny Yen), short-tempered warrior Baze Malbus (Wen Jiang), and turncoat pilot Bodhi Rook (Riz Ahmed). After some twists and turns and betrayal and heartbreak, the team finds themselves on a mission to steal the plans for the Death Star out from under Krennic’s nose.

This movie does special effects right, I’ll give it that. Especially commendable is the way CGI is used to recreate some classic characters, one of whom was played by an actor who’s been dead for over twenty years. These type of effects can become creepy and laughable very easily, but as far as I could tell the movie does it seamlessly. I actually thought they were somehow using old footage before I learned that it was new actors with CGI makeup. Elsewhere, everything from aliens to spaceships to entire action sequences would be right at home in the series proper. From this standpoint, I can see why the filmmakers thought they had a hit here.

But then the movie hits a brick wall when it comes to its script, and in particular its new characters. I could not bring myself to care one iota about Jyn, Andor, Gerrera, or Krennic. This despite Forrest Whitaker having an Oscar, Ben Mendelsohn having an Emmy, and Felicity Jones frankly being better than her Oscar-winning costar Eddie Redmayne in “The Theory of Everything.” Lower-tier cast members like Tudyk and Ahmed fare better, stealing scenes as expected, but the film doesn’t have memorable characters or performances where it needs them. Instead it relies too much on lazy fan service. One cameo proves to be a powerful presence, but all the others are there just for the sake of being there. It really makes you appreciate “The Force Awakens” and how it came up with interesting and meaningful roles for all of its returning characters.

“Rogue One: A Star Wars Story” was clearly made with a “don’t get too attached to them” attitude toward its original characters and it backfires badly. I was cheering at the end, not because of an emotional connection, but because I was glad to be done with this insufferable offshoot forever. It’s a shame too, because the technical aspects of this movie are excellent and deserve a story worthy of them. I think that about 90% of the people who worked on this movie were happy and honored to be working on a “Star Wars” project, but the writers and cast were secretly resentful that they weren’t working on an installment of the main series, so like Erso, they sabotaged their own work.

Two Stars out of Five.

“Rogue One: A Star Wars Story” is rated PG-13 for extended sequences of sci-fi violence and action. Its running time is 134 minutes.

Contact Bob Garver at rrg251@nyu.edu.