“Peter Pan” is one of those fictional fancies that seems to have bubbled up from the ether, as though it didn’t need an author, just the collective wishes of its adoring audience.

It had an author, of course: J.M. Barrie, a Scotsman who once said, “Nothing that happens after we are 12 matters very much.” A perfect thing for the author of “Peter Pan” to have uttered.

A new movie, “Finding Neverland,” uses Barrie as a character, in a broadly fictionalized story based on events from his life. Animating the film is the casting of Johnny Depp as Barrie, an apt choice if ever there was one. Yet this movie is somehow less than the sum of its good intentions.

Based on a play, “The Man Who Was Peter Pan” by Allen Knee, this is one of those speculations that traces the real-life inspirations of great imaginative works. For some reason, that always seems to diminish, rather than amplify, the classic in question.

In this case, we meet Barrie in the doldrums, personally and creatively. Stuck in a frustrating relationship with his wife, Mary (Radha Mitchell), he finds boon companions in a family of young brothers he meets in a London park one day.

His childlike personality responds to the boys, and his more adult side responds to their mother, Sylvia Llewelyn Davies (Kate Winslet). Despite the clucking of observers, he happily spends time away from his wife to be with this other family.

After entertaining the boys with make-believe about pirates and Indians, the film’s Barrie naturally turns these adventures into the stuff of “Peter Pan.” Which, by the way, had its premiere 100 years ago, in December 1904.

This leads to some fun behind-the-scenes business about working out this most unusual show (actors on wires? A dog, played by an actor, as a main character?). It also leads to considerable sniffles, as the success of the show folds together with tragedy offstage.

This movie is affecting, and it catches some nice observations about why people create and watch illusions. There’s also Depp’s performance, which is scrupulous, if lacking in the explosive inventiveness that fuels some of his best work (an understandable decision, given the material).

A couple of Oscar winners, Julie Christie and Dustin Hoffman, are very quiet in small roles. Mitchell and Winslet are sufficiently radiant actresses to make you seriously question why Barrie would spend any time with children when he could be with either of these women.

Director Marc Forster can’t find a way around the literal-minded concept of the script – that Barrie takes his playtime with the children and pastes it into “Peter Pan.” “Finding Neverland” misses the sense of mystery it wants to create, but get out your handkerchiefs anyway.

Johnny Depp and Freddie Highmore in “Finding Neverland.”

“Finding Neverland” HHH

Three hankies: Fictionalized story of J.M. Barrie (Johnny Depp), and how he might have come to write “Peter Pan” after befriending a family of boys and their lonely mother (Kate Winslet). A bit too literal in its life-into-art ideas, but the movie will definitely bring on the sniffles.

Rated: PG rating is for subject matter.

“Finding Neverland” HHH

Three hankies: Fictionalized story of J.M. Barrie (Johnny Depp), and how he might have come to write “Peter Pan” after befriending a family of boys and their lonely mother (Kate Winslet). A bit too literal in its life-into-art ideas, but the movie will definitely bring on the sniffles.

Rated: PG rating is for subject matter.

Now showing: Guild 45th, Meridian.