Tell me what happened in part 3 of the story, specifically.
I would just like to add on by saying that the story in the book is exactly the same as the original generally, but is masterfully written to "impart suspense".
The week goes by rapidly, and Beauty finally tells Grace abouyt Robbie still being alive. She then says she has to go, but her family persuades her to stay home another day. After that day, she dreams she finds the Beast lying dead at his castle, and when she wakes up she sees that the rose has begun to die. Terrified, Beauty takes off for the castle. She can't find it at first, but at last she arrives at the castle and finds the Beast in the condition she found him in her dream. She tells him she is sorry and she won't go away again, and the Beat tells her he will be all right. Not wanting to waste anymore time, Beauty tells him she loves in and will marry him. At that moment, everything explodes in light, and when the castle and gardens return to her vision, she sees not the Beast standing before her but a man. He is rather stately, and she protests that she can't possibly marry him because she is far too plain. He takes her to look in the mirror and she finds she is wearing grand clothing, and all the grime from her journey has been washed away. The invisible servants all become visible again, and her family comes to find her in the castle. Robbie has arrived to be with Grace by this time, and Melinda is seen with Beauty's father. All together again, they hold a triple wedding at the castle, and everyone is happy. The End!
Beauty travels to the Beast's castle in order to save her father from being killed. When she arrives, the Beast tells her he just wants companionship, and that he wouldn't have actually hurt her father if Beauty had not decided of her own free will to go to the castle. The next chapters describe her getting settled in the castle. The Beast shows her his massive library, which includes books that haven't even been written yet. Beauty takes her favorite horse Greatheart out riding, and eventually coaxes him into trusting the Beat. At night, in the weird time between full sleep and full wakefulness, she hears disembodied voices talking about how she is the last hope for something, and that she doesn't understand yet why she has been brought to the castle in the first place.
As time passes, Beauty becomes more and more comfortable with the Beast. They eventually start up a tradition of reading to each other, and Beauty begins to wonder at her feelings for the Beast, and admits that her reasons for looking forward to every meeting with him aren't purely because of being lonely in the big castle. She finds life there quite enjoyable, and only the fact that she misses her family terribly and the Beast asks her every night if she will marry him cause her any discomfort.
Her homesickness leads her to finally ask him if after some time she can go back home, and it is during this discussion that she learns the Beast cannot ever let her go. She screams to be released and faints. When she comes to, she is shocked to find that she had been sleeping in the Beast's arms. It freaks her out, which eventually leads her to wonder why it rattled her so much to find she had let the Beast touch her.
The disembodied voices from before show up again, and this time they mention some evil magician, but Beauty can understand no more of the invisible people's words.
More time passes, and Beauty trusts the Beast even more, yet she still refuses to marry him when he asks her. One night she has a dream about her family that seems so real, and upon telling the Beast about it she learns that he sends her family dreams about her to comfort them. He then takes her to a table with a glass on it, and after he pours something onto the table and places the glass over it, Beauty can see what is actually happening with her family as if she were there, too. She watches as Grace laments losing her love Robbie and says she doesn't want to have to say yes to a proposal from the minister Mr. Lawrey. When Beauty wonders what happened to Robbie, she sees in the glass that Robbie was shipwrecked but still lives. Beauty asks Beast to send another dream to her father telling him that Robbie is still alive, but the Beast explains that it won't work. Beauty begs him to let her go home and tell Grace that Robbie is still alive, and the Beast finally agrees to let her go for a week. He gives her a bowl of water with a rose resting on it and says it will be fresh for a week, but after that it will wither and die, and at that point she will know that the Beast is dying, too.
Beauty makes her way home, and everyone is delighted to see her. They exchange stories, and in her attempts to tell them about the Beast she involuntary stumbles upon the realization that she loves him. She glosses over the thought for the time being and goes on to other subjects. Her family is devastated to learn she is only there for a week and must then go away forever.