In part one, Bella and Edward finally sparkle in the bedroom and make a baby. In part two, Jacob and Edward conspire to force Bella into an abortion and fail which ends up being good for Jacob because he "imprints" on Bella's baby (it's totally platonic!). Now, part three, in which stuff actually happens. Like, vampire stuff.
So, when Edward injected Bella in the heart with his venom (saliva), it hurt. In the Twiverse, changing to a vampire is painful. In the first book, Bella was bit in the hand, and she was screaming because it felt like her hand was on fire. Now in Breaking Dawn, Bella is all, "I'm in pain, but I won't cry out. I won't even say a word and they'll think, 'oh, she's such a good girl. She won't even cry.'" The reality is that Bella is in a lot of pain and it's freaking the Cullenses out because they're expecting her to cry and scream and otherwise feel horrible, but Bella just had to jump up and nail herself to a cross so she won't be a bother to anyone. What a freakin' martyr. Jeez.
When the pain finally leaves, Bella wakes up and gets all freaky at the Cullenses, who have never been anything other than nice to her. Her fear instinct kicks in, and she does Shaolin acrobatics above everyone's heads, flipping away from them all Crouching Tiger Hidden Dumbass. As with the rest of the books, it takes Bella a long time to locate the various parts of her body such as legs, feet, hands, lungs, etc. She remembers being pregnant and is all, "Bring me my baby, yo!" and for some reason, the idiots around her are like, "We don't know if that's a good idea." Bella is understandably pissed by this because she's gone to such lengths to protect her little Renesmee (despite giving her the stupidest name since Mitt), she sort of deserves her baby.
Finally, everyone decides that she can see her kid, and I don't have kids, so I'm probably not qualified to say this, but if anyone dared get between me and my sprog, I'd kill them. Dead. Bella instead passively makes her case until they lead her to the living room where Jacob is holding Renesmee (ew! If he changes her diaper ever, I will have to send his name to Chris Hanson) and feeling unwilling to let Bella have her. Bella is now the enemy to Jacob. Not because she's a vampire, but because she's a potential threat to his Precious. Bella tries to take her baby from the pedophile, and he won't let go of her. Bella is like, "What the heck, Jake?" and he's like, "I can't let you hurt her." and Bella's all, "She's my baby, you just move on your way. I said good day, sir!"
Now, when Bella was faced with Stalker!Edward before she knew he liked her (blood), she was passive. When Charlie unhooked the battery of her truck, she was passive. When Edward decided to leave her, she had a little fight in her, but in the end she fell asleep in the woods and turned into a zombie, which I'm pretty sure is passive. Edward removed parts from her car, passive. Alice decided to plan Bella's wedding without any input from Bella, passive. The only time Bella has fought was for her child, so I totally wasn't surprised when she tried to rip Jacob's throat out. What surprised me was that no one let her.
He's an eighteen-year-old man. Renesmee is a baby. He does not get to ever touch her ever. He is a pervert. I don't care how hard Smyers tried to convince us that he feels only platonically for her until she comes of age. This is not how you make people like a character. It's disgusting and vile and foul and gross and wrong. And he's living with vampires who have lived for hundreds of years, and none of them are like, "Dude, you need to leave." NO! Plus, Jacob makes this case about how he'll get depressed if he's away from the baby for too long. Dude! It's not a baby's job to make you feel good about yourself! You're an adult, go act like one and get the heck away, where you should have been since Bella said "yes" to Edward's proposal. Grow a pair and walk away. But noooo...
Anyway, the Cullenses stop Bella from killing Jacob, and Renesmee lets Bella know that the whole scene scared her and that she likes Jacob and she does this by putting her hand on Bella's cheek. I hope Bella has nice skin, because that's how you get pimples. Seriously, don't ever touch your face.
Anyway, all sorts of boring stuff happens after that. Edward takes Bella hunting for endangered species before retiring to their little cabin for the night. Alice and Esmee built a little cabin for them and decorated it for them and put clothes in the closet for them because God only knows that Bella just would never want to have a cabin that suited her own tastes with her own decorating style and her own clothes in the closet. I really get annoyed by Alice. She's so high-handed. Carlisle told Jacob at one point that Alice doesn't like them wearing the same outfit more than once, like that's her job in the family or something. If you want to know why Edward wears nothing other than beige, look no further than Alice. She stocks his wardrobe.
At first, Bella is unimpressed with the clothes and shoes Alice has supplied her, but by the middle of the third part, she's just putting on whatever is there. Angora suits. Cashmere shifts. Oyster-colored satin cocktail dresses. Everything is ecru and eggshell and off-white. In the first book, Edward loved how Bella looked in her blue sweater. I guess he'll never get to see her in a color again.
So, the stuff that happens. Basically, the Volturi hear about Renesmee and decide it's the perfect opportunity to kidnap Bella so they can figure out her gift, which they reason must be really interesting since no one could touch her with their ability in the second book. They're right. The Cullens summon as many allies to their house as they can try to keep their family intact and everyone thinks that Renesmee is a turned child at first, until the Cullens explain what she is. Alice disappears (yay!) on some crazy mission, leaving Bella a rabbit trail to follow which leads her to a guy who can forge papers. It takes Bella a long time to parse out why Alice would send her to this guy, and then she realizes that if everything goes pear-shaped, she's going to have to send Renesmee and Jacob away together, so she has papers made for them.
The cool part is that the forger gets sort of funny at the end and asks Bella if she's planning on kidnapping the little girl. Bella finally says that Renesmee is her daughter, and the guy is relieved, showing that he has some sort of conscience.
The part of this that made me feel a little funny was how Bella got the money to do it all. She snuck through the house and took the money from the drawers and closets where the Cullenses hide their money. I mean, they apparently have thousands just laying around the house and Bella had to "steal" it. I'm assuming that Alice left money here and there for Bella to find because if she had just given Bella money, it would have been suspicious. But Bella feels bad about taking the money. Like it isn't hers. But isn't it? She may not be able to buy her own clothes or cars or anything, but surely even a vampire needs pocket change? Everything in this family is considered communal, and I'm sort of surprised that Carlisle never showed Bella the drawers where the money is kept and is like, "So, if you ever need some cash, here you go. You never know if Ralph Lauren put out a camel-colored sport coat that Alice doesn't know about." Why hasn't Edward given Bella her own money drawer? I know this is an odd thing to wonder about, but if they're fabulously wealthy and own everything outright and only really have to pay for utilities and gas and sundries like that, then why doesn't Bella have her own allowance? Anyway, that's all.
There are other preparations that include the whole family and their allies, and Bella starts figuring out her gift. Apparently, she's a shield who can cast out a "net" of protectiveness away from herself, so when the Volturi come, Bella is able to keep them from using their super-powers on the people around her. there's a huge anti-climactic "war" where Bella puts a backpack containing the forged papers and a bunch of extra money on Renesmee's back, and puts Renesmee on Wolf!Jacob just in case he needs to run off with her. Edward's all, "I knew you were keeping something from me!" and Bella feels guilty about it, but the bottom line is that if something happens to Edward, Bella doesn't want to continue living. In that case, it would be best if Jacob just ran off with Renesmee because she wouldn't have any parents left, anyway. I mean, why would someone want to continue living if the love of their life died? Right? These people are so selfish.
After a whole lot of talking, Alice and Jasper return with some interesting people. People who are just like Renesmee. It turns out that there's a vampire in South America who's going around impregnating women, and Alice has one of the offspring of this guy. Vampire/Human hybrids apparently grow at an alarming rate (which is why Renesmee looks like she's six when she's only one), but then stop growing and remain that way forever. This is great news for Bella, who has been afraid that Renesmee would be dead in twenty years after having lived to old age in that timespan. Edward's all happy because he thinks the new humpire will be competition for Jacob, but Bella's not worried because she's sure Renesmee will always be with Jacob, which is a really terrible thought to have about your one-year-old. Since they're all going to be immortal forever, I don't see why Renesmee can't have both, but again that doesn't exist in the Twiverse.
The Volturi decide to leave the Cullenses alone for whatever reason, which doesn't really sound right to me, but apparently that really is the end. I mean, here are tons of people with really awesome gifts, and The Volturi are basically the royalty of the vampire world. There is no reason that they should leave, and no reason that they should be refused if they want some of the vampires with extraordinary gifts. I sort of wish there was a League of Extraordinary Vampires going on somewhere. They'd be morally ambiguous, doling out punishment and stealing famous artifacts, maybe searching for the Holy Grail or something. Sorry, it's hard not to think of ways to improve this really dull book.
Anyway, that's the end. Everyone lives happily ever after because of course they do.