This is the second volume (chronologically) in The Chronicles of Narnia (after The Magician's Nephew, before The Horse and His Boy; Prince Caspian; The Voyage of the Dawn Treader; The Silver Chair; The Last Battle).
This book takes place during World War II, many years after the events of The Magician's Nephew, and tells the story of four young siblings, Peter, Susan, Edmund and Lucy. They are exploring the big house of an old Professor (which I'm guessig is Digory from the first book) where they've been sent during the air-raids, when Lucy enters the old wardrobe in en empty room upstairs to hide in it.
Only this wardrobe is actually a direct passage to the world of Narnia, and Lucy finds herself in a forest on a snowy night, the only light that of a lamppost. There she meets a Faun named Tumnus, who is indeed very amazed to meet a legendary Human, an invites her to tea. In the cozy warmth of his home, he tells her of the evil White Witch, who is turning everyone who opposes her to stone, and whose spell on Narnia makes it always winter and never Christmas.
When Lucy finally gets out of the wood and then out of the wardrobe again, no time has actually passed, and of course, when she tells her story to her brothers and sister, none of them believes her. Edmund in particular likes to make fun of her.
On another, rainy day, when they're all playing hide-and-seek in the huge mansion, Edmund decides to hide in the wardrobe and he too finds himself in Narnia. But instead of the Faun, he meets the White Witch, who lures him with Turkish Delight (his favourite sweets) and by making him believe that he can become King if he brings her his brother and sisters.
The book then tells the adventures of the four kids in Narnia, meeting a friendly couple of talking badgers and all kinds of other fantastic animals and creatures, among then the powerful Lion King Aslan, and helping them save the world from the evil usurper Queen.
Reading the series in the chronological order rather than in the publication order, I found that The Magician's Nephew was actually a kind of spoiler for The Lion, the Witch and the Wardrobe. I think that I would have been more enchanted, amazed and curious about the world of Narnia if I hadn't read all about its creation in the first book. I would have wondered about the lamppost, for example (and it would have been nice to read about the Lion's song later). Knowing about it in advance, I'm sure I found it a tad duller, because I wasn't discovering it at the same time as the kids. This is a nice story, and I know it's a Classic, but I must say it's not as captivating as I thought it would be.
I advise you read it in the publication order: The Lion, the Witch and the Wardrobe; Prince Caspian; The Voyage of the Dawn Treader; The Silver Chair; The Horse and His Boy; The Magicians Nephew; The Last Battle.
