This movie has quite a major twist, you won't have seen it coming.
After he rescues Solara (Mila Kunis) from the rapist-murderers, they travel West together until they find a lone white house. In it are two old people that have survived up to now thanks to a few booby-traps house and an arsenal of weapons. They offer the guests some tea, but as its served the lady obviously has the shakes - a neurological condition urban-legend caused by eating too much human red meat that the movie writers have jumped on.
Eli and Solara panic and try to get out, but Carnegie (Oldman) and his gang pull up in armored cars. There's a huge gun-fight, but a few RPGs takes away most of the walls to the house, kill the old couple and Eli/Solara have no choice but to surrender.
Eli won't give up the book, the Bible - the last one in existence. Carnegie holds a gun to Solara's head and Eli gives in. Carnegie takes the book, gives Solara to his right-hand man and shoots Eli in the chest. They leave him to die, and he can't belive his mission is over.
On the Nevada road back to town, Solara flips the car they're in, killing Redridge by accident with Eli's machete, and hurls a grenade under the other van closing in on them. She jumps in the flipped car that landed on its wheels, and drives back to Eli. Carnegie, low on fuel in the remaining security truck, decides not to chase.
Eli is not at the house. She drives West and finds him on the road, walking. He hitches a ride and they make it to the ocean and the Golden Gate bridge.
Looking out towards 'The Rock', Eli knows that is where the book needs to be. They row out and make it peacefully past some armed guards. Inside, Malcolm McDowell shows them a museum collection that he is planning to use to bring civilisation back to the world.
Carnegie and the shopkeeper prize open the lock to the book -- but find that it is written in Braille. Solara's mother tells him she has forgotten how to read it, but that he will be dead soon anyway as infection has set in to his leg, and without his men the townpeople are breaking up the bar downstairs.
Eli removes his glasses to reveal his is, in fact, blind. He tells McDowell to get a pen and a lot (!) of paper, and then starts to recite the Bible that he has read and memorized over the past 30 years, starting with Genesis - 'In the beginning...'.
The book is finished, printed on a press they have, and bound. Eli dies and is buried in the grounds. As we hear Eli's final prayer of thanksgiving and protection for his friend, Solara takes his machete and ipod, and although McDowell wants her to remain, she decides to head East, back home.