At the outset of “Robin Hood” (2018 edition), the narrator tells us we should forget everything we think we know of the “bedtime story” about the legendary outlaw who stole from the rich to give to the poor.

At the conclusion of “Robin Hood” (2018 edition), I was fervently wishing there was a way to forget everything I had just witnessed and go back to what I already knew about that bedtime story.

Somehow, some way, a great number of people (including some genuine talents on both sides of the camera) agreed it would be a grand idea to re-imagine the story of Robin Hood as a mashup between a slick, cynical, mediocre action-comedy buddy movie from the 1980s, a cliché-riddled war film and an uninspired video game.

From the often anachronistic (and terribly unfunny) dialogue to the insanely over-the-top pyrotechnics to the uneasy blending of practical effects and CGI to the unfortunately overwrought performances to the unintentionally funny plot twists, “Robin Hood” has all the ingredients of a serious contender for Worst Movie of the Year.

Taron Egerton (from the “Kingsman” movies) plays Robin of Loxley, a soft and spoiled lord of the manor in Nottingham who has the hair and the dental work and the attitude of the leader of a boy band maybe two years past its prime, even though this story is set approximately 800 years ago.

When Robin catches a plucky, sass-talking, would-be thief (Eve Hewson) trying to make off with one of his horses, he tells her she can have the horse — if she’ll tell him her name.

It’s Marian. Maid Marian.

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Thus begins a fairy tale romance — but the fairy tale is fractured when Robin is drafted to fight in the Crusades.

Flash forward four years. We catch up with Robin as his unit embarks on an invasion of an Arabian stronghold that results in much bloodshed on both sides, and many highly stylized, sometimes even slo-mo sequences of combatants flying through the air and performing feats of acrobatic killing.

Robin is gone so long that, like the Tom Hanks character in “Cast Away,” by the time he returns home, everyone has long assumed he was dead. (In fact, there’s a scene in “Robin Hood” in which an old friend talks about the memorial service, a la “Cast Away.”)

Marian is now with the politically ambitious man of the people Will Scarlet (Jamie Dornan), who has a pronounced Irish accent even though we’re not in Ireland — but they’re hopelessly overmatched by the forces of the corrupt Sheriff of Nottingham (Ben Mendelsohn), who seems to have cornered the market on three-quarters length, powder-blue leather jackets offset by tastefully muted wool vests and a haircut with just the right edge.

Jamie Foxx plays a great Arab warrior who barely survives that aforementioned invasion, stows away on a ship bound for England, tracks down Robin and recruits him to join his mission to overturn the Nottingham regime. When Robin is unable to pronounce the warrior’s name, the warrior tells him to go with the English translation:

John. As in, Little John.

We get similarly heavy-handed “origin stories” about a few other familiar characters from the Robin Hood legend, set against the backdrop of third-rate plot machinations and eardrum-rattling battle scenes. And in arguably the most regrettable sequence in a movie filled with questionable moments, John trains Robin in a montage straight out of a “Karate Kid” or “Rocky” movie.

It’s legitimately funny. Not sure that was the intention.

Egerton is miscast. He and Hewson have nary a spark in their love scenes. Dornan overplays his hand. Foxx belts out nearly every line as if he’s trying to be heard above a parade of fire engines on a Fourth of July parade — but after the appearance of F. Murray Abraham and F. Murray Abraham’s truly unfortunate wig, Foxx’s is only the second-worst performance by an Oscar winner in this film.

‘Robin Hood’

Summit Entertainment presents a film directed by Otto Bathurst and written by Ben Chandler and David James Kelly. Rated PG-13 (for extended sequences of violence and action, and some suggestive references). Running time: 116 minutes. Opens Wednesday at local theaters.