Martine is the illegitimate daughter of an important guy in Anglo-Saxon England. She grows up loving her father, not understanding that her mother is his mistress, until her father's actual legit wife dies. Martine's mother makes a wedding dress and is certain that now that he's free, he'll marry her and everything will be great. But he marries some little fifteen-year-old and completely cuts off Martine and his mistress from his support. Martine's mother is so distraught that she commits suicide, leaving Martine to die of starvation, until her father's legit son (and thus her half-brother) Rainulf finds her and saves her. He takes her to a convent, where she learns how to be a person, but she's not trained in how to be a lady. And while her father is a cousin of the queen or something, Martine's relationship to the queen is the kind that, uh, well, people would be super judgy about if they knew.
Thorne Falconer meets Rainulf while they're in the Crusades, taken captive and starving and going crazy. Thorne is Saxon and uneducated, so Rainulf teaches him French and English and general "how to be a decent guy" things. Thorne goes to England once he's released, and becomes a knight for Godfrey, who has land holdings and two 10000% dickish sons, Bernard and Edmond (damn it Edmond!). Bernard's married to a barren wife, and Edmond isn't married, but they're both into killin' prostitutes, and huntin' and falconin' and other Man Shit, so there's that! Thorne has no land, though, and he wants land so he can be a Man.
Rainulf wants to go... do something? It'll take like 2 years and he'll be traveling a lot, and he can't take Martine with him. So, for shady plot reasons, Rainulf contacts Thorne, who sets up a marriage between Martine and Edmond. In exchange for getting Edmond a wife who's related to the queen (...kindaaaaa???), Thorne will get some land.
During the trip to England from France, the boat's in a storm and Martine gets pissed and, anyway, she's a sassy kind of entitled girl and she sasses the crew and they're like "you do witchcraft!" and she's like "GIRL YOU WISH. But how about you just NEVER TALK AGAIN," to the captain. Or some shit. It was a long time ago.
So the first person Martine meets is Thorne, and she's like "...maybe marriage won't be so bad," but then she finds out Thorne isn't Edmond and she's embarrassed, and also super defensive because she's so angry about what happened to her mom that she's determined she will never love anyone ever EVER SHUT UP.
Martine meets Edmond, and at the time he has blood on his hands and she's like FUCK THIS SHIT, but everyone's like "I'm sure he's fine," even though he's a total fucking sociopath. They have a celebration picnic and this little girl who has bonded with Martine drowns. Her name's Ailith. Martine, who carries around medicinal herbs and knows things because she hung out with physicians, resuscitates Ailith after Ailith has been pronounced dead. The local priest asshole is like "witchcraft! That girl was dead and God wants her dead!" and Martine is like "fuck that noise." And so is Thorne, who is like "....damn I am really liking this woman."
Also Bernard's wife (again, barren) notices that Thorne's into Martine and she copies Martine's perfume and dresses like her and catches Thorne asleep and has sex with him pretending she's Martine, and by the time he figures it out, uh, well, he didn't have time to pull out, and... oops. Bernard's wife is like WHEEEEE I HOPE I HAVE A BABY! Also she's a bitch.
Martine finds out about this and thinks Thorne's a man-whore, which isn't too far off. The night he meets Martine, he like fucks a kitchen maid in the hallway cause he's got a raging hard-on and ain't got time to deal with it himself.
Anyway. Martine and Thorne end up having sex on a riverbank (shut up, at least it wasn't IN the fucking water, although he's referred to as "fighting with a beast within" when he tries to deny his raging hard-on for her, and then when he gives in it's like "the bear is loose" and oh sweet baby gherkin that was ridic) and he takes her virginity, oops. And they're both like "yeah that was great but whatev." Martine knows that Thorne's land deal is contingent on her marrying Edmond, who, again, sociopath. Thorne has nothing to offer Martine, although he also thinks she's smoking hot.
So, Martine marries asshole, and he's afraid of her (again, the whole witchcraft allegations) so he doesn't even try to consummate until a week in, and Martine drugs his wine so he'll pass out but he doesn't drink wine before trying to fucking CHOKE THE LIFE OUT OF HER AND RAPE HER LIKE HE DID TO THAT UNFORTUNATE PROSTITUTE, and then he has some wine before he can get too far, but still. He still beats the shit out of her; he just doesn't rape her.
She manages to run away, and Thorne finds her and nurses her back to health, and they try to get the marriage annulled (it was never consummated), but one way to do that is "I mean is she a virgin?" and oops she isn't. So Martine decides to just stay at the local monastery, like, forever. The monks say it's okay as long as, um, no sexytimes. With Thorne. Cause everyone knows y'all doin it.
Thorne's wounded when trying to break into a local castle, thanks to another subplot, and brought to the monastery, where Martine nurses him back to health, and they... have cautious sexytimes because, like, Thorne's super wounded. And they're clearly in love and clearly in denial. Martine thinks she's weak like her mom and Thorne's like "I'm too MANLY to be in love."
Bernard's wife dies in what she thought was childbirth, but she probably had some massive tumor. She thought it was Thorne's baby but it was, again, tumor hellspawn. Edmond dies around the same time thanks to drinking and (horse) driving. Martine's a landed widow!
So Bernard's like "hey y'all Imma marry Martine tomorrow" like before his wife's corpse is even cold, and Martine's like "how about fuck no," but anyway she can be compelled and shit. Life is hard for ladies in pre-indoor plumbing times, yo. So she breaks out and runs away, and Thorne finds her and he's like "hey girl let's get married" practically while his dick is still inside her (because yes of course they have sex again) and she's like "...yeah sure 'cause you just stick your dick in anything that's willing and whatev."
Bernard finds out and is like "well played. BUT FUCK YOU BOTH. [evil laugh]"
The queen gives Thorne the castle that he was wounded while trying to capture! And Martine is happy because she has a garden and a house and Thorne's trying to be nice to her but yeah he wants to get all up in there. And she's like "whatev just get it over with" and he's like "noooooo," but they have a little fight and he runs away to Hastings. Martine tells him to go there and fuck a prostitute if he just needs to rub one out, but instead he gets drunk off his ass and Bernard busts into the castle and is like "hey bitch WITCHCRAFT."
So Martine is put on trial for witchcraft and nearly gets out of it, thanks to one of the monks, and then Bernard pays the ship captain to say she made him mute, and they're like "hey girl haaaaay BURN HER" but Thorne gets to spend an hour with Martine the night before she's gonna be burned at the stake so they can make sweet sweet love, and then he gets the ship captain to admit the truth, and so everything's okay but Bernard's like "yeah bitch you still gonna burn" and Thorne kills him with an arrow! So hooray they're going home together and they're in love and awwww.