Lady Renegades by Rachel Hawkins

 The book begins with a prologue from David's POV. He is in Mississippi and is now having near constant headaches. He gets visions all the time and his eyes are permanently golden and glowing. He eats very little and sleeps even less. Worst of all, his visions are all blurry and disjointed, and when they come on him, it seems he unwillingly turns any young woman who happens to be near him into a Paladin.

Meanwhile, Harper has been working as a lifeguard with Bee and bored out of her mind until one day she is attacked in the pool locker room by a girl claiming to be another Paladin. She tells Harper she is there to kill her because it's what David wants. While fighting, Harper feels herself losing all her strength, and only narrowly avoids death thanks to Bee finding her in time. 

In a desperate attempt to find David, Harper gets Bee and Ryan to attempt a summoning ritual at the ruins of the old Ephor house. The spell doesn't seem to work, except that night they all have dreams they feel may be the same ones David is dreaming. The next morning, while having lunch with her family, Harper is shocked when Blythe (who she thought was dead, drained of her magic by Alexander), shows up and "reboots" her Paladin strength.

Turns out the spell the three did to try to find David actually ended up summoning Blythe. Blythe shows them a newspaper article about a girl who woke up with amnesia in Alabama having no idea how she got there from Mississippi and talking about a man with glowing eyes. Blythe tells the trio she is there to help them find David and make him stop creating new paladins before his powers consume him and he destroys everything around him like the last male Oracle did. They decide to go on a road trip to locate him, but before leaving Bee and Harper have Ryan draw protection runes on their bodies, which they get as tattoos, for more permanent protection.

The first stop on the journey is Mississippi, to try and find the girl who attacked Harper at the pool. She tells them she felt David was two completely different people, at war with himself - one side wanting to kill Harper and one deeply in love with her. The girl warns Harper that the part that wants her dead is getting stronger and stronger. Later, at a seedy cheap motel, Harper is attacked by the front desk clerk, who has also been paladined by David. Harper is able to subdue her with Blythe's help, but not before the girl tells them that the reason David wants Harper dead is because he thinks Harper will be the one to kill him.

Later, the three girls arrive at Saylor Stark's childhood home, where Blythe believes Saylor left a spell that will help them free David. While at the house. Saylor's brother tells them a boy had been by looking for something before, but was unable to find it. The boy, though, was not David, as Saylor's brother describes him as a tall, handsome, Asian teen. Blythe later tells Harper this had to be Dante, another mage and Alexander's assistant. While the girls do find Saylor's spell book, the last few pages have been ripped out, alerting them to the fact that Dante had beaten them to the spell they needed. At this time, both Harper and Bee have a vision unlike anything they have experience before. They feel themselves transported to a cave where a dark haired boy is himself in the middle of a vision. They assume the boy is Alaric, the first male Oracle. 

By using Saylor's book and stories about Alaric, Blythe realizes David appears to be on the same path as Alaric, who just before going nuclear Oracle, locked himself away in a cave and performed rituals to super-charge his powers. Harper wants to find David first, but Blythe tells her this won't do any good because they can't stop him without the spell Dante stole. 

They find Dante at a bar in Georgia, where Blythe promptly knocks him out with a very large can of hair spray. When he wakes up though, they realize his mind has been wiped, and he seems to have lost all of his mage powers. Blythe uses magic to dive into Dante's vision and they realize that what happened is that Alexander used Dante to test the spell meant for David - which involved a memory wipe and removal of his powers. The mind dive also seems to awaken Dante's powers and he attacks them with magic powerful enough that Harper has to knock him out cold with a large toolbox. 

The three head for Alexander's old Atlanta office (after dumping Dante and calling 911), hoping to find the spell among what's left of Alexander's things. While rifling through Alexanders papers they discover something shocking: Alexander was actually David's biological father, and his biological mother was the last female Oracle, and that Alaric had also been the son of a female Oracle. They also find some pages of the spell from Saylor, which freaks Blythe out because she says it's intensely complicated magic. There also seems to be a missing section of the spell - something beyond wiping David's memory and removing his powers, which had been alluded to by Dante in his last memory.

While at a flea market looking for spell supplies, Harper is strangely drawn to an old sword, which she buys. Harper is once again attacked by a new paladin, this time though, both Harper and Bee are completely powerless to defend themselves. It's only because of Blythe's powers they manage to subdue the girl. Blythe thinks the girls powers are finally gone for good, and that it may be too late to stop David from beginning the final ritual to make himself ultra powerful. Blythe tells Harper she will probably have to kill David. Blythe explains that with her powers intact, it would be impossible for her to kill David, but her powers being gone means, in Blythe's mind, that Harper can now kill David. 

Harper is not happy with this and she and Bee attack Blythe, knocking her out and running away in search of David. Harper's psychic connection to David leads her and Bee to a forest in Tennessee where Harper finds David alone deep inside a cave. Except what she sees is not David, but an illusion of the David he used to be. Harper moves father into the cave, finding David, dirty, disheveled and with glowing eyes, having been completely overcome by the oracle powers. Harper tries speaking to the oracle, trying to remind him of David and how much he was loved. This seems to be getting through somehow, until they are interrupted by Blythe and Bee. 

David is poised to fatally attack Blythe and Bee, but Harper is faster and runs him through with her sword. David dies, but Blythe start babbling something about him being only a little bit dead, and that she can fix him. Harper does not wait to see what she means though, and simply walks out of the cave and goes back home. 

A few weeks later, Bee and Harper start their Senior Year when Harper quite literally runs into David in the Headmaster's office. He is accompanied by Blythe who is pretending to be his sister. Everyone at school thinks David is a new student, and Harper realizes she has another chance with the boy she still loves.