“All good stories deserve embellishment.” This is not a sentiment to be found in J.R.R. Tolkien’s slim novelThe Hobbit, but it’s uttered by the wise wizard Gandalf near the very expected beginning of An Unexpected Journey.

It’s obviously co-writer and director Peter Jackson’s belief as well. Jackson’s Lord of the Rings trilogy mirrored the structure of Tolkien’s book, to the delight of a legion of fans and many new converts. But The Hobbit is a relatively brief and simple quest, as evidenced by the book’s subtitle: There and Back Again.

Turning this one into three massive pictures stretches the boundaries of good sense, good taste and patience. Jackson’s explanation, that he worked in material from Tolkien’s extensive appendices, also smacks of disingenuousness. What if Sam Mendes had included martini recipes and a primer on ejection seats in a bid to turn Skyfall into a two-parter?

But here we are, diving into a vertiginous back story about the wondrous city of Erebor, laid low by a dragon named Smaug. Sixty years later (and 60 years before the events ofThe Lord of the Rings), a group of dwarves decides to head back, kick out the dragon, and reclaim their gold and kingdom.

Their leader is Thorin, son of Thrain, son of Thror. (These are the kind of spittle-producing introductions that will nicely boost a film’s running time, especially if you travel with 12 other dwarves, each with his own proud lineage, which is exactly what Thorin, son of Thrain, son of Thror, does.) Played by Richard Armitage, he’s a redoubtable dwarf, 5-foot-2 if he’s an inch.
The company arrives on the doorstep of Bilbo Baggins, perfectly embodied by Martin Freeman. He’s become known of late at Dr. Watson on TV’s modern-set Sherlock Holmes series, but his quintessential (or at least most relevant) role is probably that of Arthur Dent, Englishman and homebody, from The Hitchhiker’s Guide to the Galaxy. Middle-earth and middle-Essex are each home to a certain kind of reticent hero, and Freeman plays both with ease.

Gandalf and the rest of the dwarves — whose names, if you must know, are Balin and Dwalin, Bifor, Bofur and Bombur, Fili and Kili, Oin and Gloin, Nori, Dori and Ori — convince Bilbo that a spot of adventure would be just the thing to write home about, and they set off across a landscape so breathtaking, it’s as if New Zealand and Photoshop had a baby.