Danny Boyle and Richard Curtis imagine a world without the Fab Five.

It’s summertime, and your multiplex is packed with the usual fluff – franchises and remakes and some repurposed Disney.

If an original concept comes along, one that can be defined in a single, intriguing sentence, summer audiences are easily hooked.

In “Yesterday,” we are told that the Beatles never existed and their lost music exists only in the mind of one single person.

Himesh Patel and Lily James make an attractive couple in music fantasy.

Intriguing premise, right? How would pop/rock have developed in a sans-Beatle world? Would there have been any Rolling Stones? Animals? Dusty Springfield? The Who? The Kinks? Tom Jones? Any British invasion, period? How would American music have developed? The Beatles may have been the greatest influencers of the 1960s, but they in turn were hugely influenced by American music considered “troubled,” i.e. not liked by white parents, who tried to marginalize Elvis, Jerry Lee Lewis, and any black rock’n’roll artists by having them banned, or at least segregated, on the radio.

None of these questions are of interest to the men behind “Yesterday,” writer Richard Curtis and director Danny Boyle, who appropriated a story from Jack Barth, a moderately successful TV-writer. In a recent article in the Wall Street Journal, Barth described how his cynical screenplay about a failed writer was totally reworked by Mr. Curtis, who is known for his happy movies with very happy endings – “Four Weddings and a Funeral,” “Love, Actually,” “Notting Hill,” and a couple of “Bridget Joneses.”

Movie follows a busker dropped into a world without the Beatles.

An out-and-out comedy, then, is what we get in “Yesterday.” British actor Himesh Patel is Jack Malik, a moderately successful (read: not at all) singer-songwriter in a small English town has just about decided to give up his career as a busker. At least there is money in teaching, his former day job.

Bicycling home from another failed gig, Jack is hit by a bus, ends up in a hospital, toothless, and is fussed over by his best friend and manager, Ellie (Lily James). He makes a weak joke about “When I’m 64”, a joke Ellie doesn’t get. Days later, recuperating, he picks up his guitar and plays the Beatles’ most famous song for her and some friends. Their reaction to “Yesterday,” a song that has been covered by more than 3,300 artists, is unexpected – they claim they have never heard it. Jack is declared a musical genius and urged to write more music “like that one.”

A couple of Google searches tell Jack the Beatles don’t exist. Nor does Coke, the drink (Pepsi rules), and smoking hasn’t been invented either. These odd changes, and some others, have been caused by a glitch in the universe. The world stopped for a couple of seconds. When it started up again, Jack was either tossed into an alternative universe, or the bump on his head has led to an experience like Bing Crosby’s in “A Connecticut Yankee in King Arthur’s Court.”

An inevitable path to super stardom must follow for the creator of this “Yesterday” song, and Jack plunders the Beatles songbook as fast as he can, not paying any attention to meaning of the songs, how and why they were created and when. There is a certain stylistic difference between “Love Me Do”(released 10.5.62) and “A Day in the Life” (released 5.26.67)…

YouTube is his friend, and so is pop star Ed Sheeran, who discovers Jack, brings him along for a Moscow gig (“Back to the U.S.S.R.” is a given, retro, hit), and on to L.A. and the grasping hands of a star-making agent (Kate McKinnon).

There might not be the Beatles, but there sure is James Corden.

A love story develops (finally, after years in the making) between Jack and Ellie, but the new pop star’s main conflict is with his conscience. He knows his success is stolen, but the money, and the adulation… it’s hard to give up.

“Yesterday” follows Richard Curtis’s traditionally happy movie thread with the expected obstacles and solutions and, naturally, happy ending. There is only one surprising scene, where Jack tries to bridge the gap to the Beatle world he knew.

The presentation of the Beatles classics ought to have been grander than the snippet-like mix we get here. Himesh Patel has a pleasant singing voice and is believable as the dejected singer-songwriter set for stardom. Able supporting cast; I especially enjoyed seeing Sanjeev Bhaskar as Jack’s dad. He has a small part in “Good Omens” and is the co-lead in “Unforgotten” on PBS.

“Yesterday” made me think of an earlier homage to the Beatles, “I Wanna Hold Your Hand,” which truly explained Beatlemania. It was made in 1978, when all the Beatles were alive, which made it less of a portentous statement, and more a fantasy of fandom, with the sheer pleasure of discovering new, different, music, and falling in love, just a little, with four fabulous boys in forbidden hair.