Ella is "blessed" with obedience as a baby, and this colors her entire life. After a childhood playmate finds out about her spell and abuses it, Ella's mother forbids her from telling anyone about the spell. Whew! Now, no one will ever abuse it… except for people who figure out that something funky is going on. This sets us up for some major hijinks.
Ella's mom dies. Major bummer. Her dad sends her off to finishing school. Obviously not so bad, but still not great.
She's stuck with the obnoxious company of two sisters, Hattie (a selfish brat who figures out Ella's obedience thing) and Olive (who is too stupid to figure anything out). Since Ella doesn't get along with Hattie and Olive or with the teachers at her school, we're thinking "conflict" is an accurate description of this part of the plot.
Hattie is making Ella's life worse by the day, and since Ella thinks she has a shot at finding the fairy Lucinda, who'd cursed her, she runs away from finishing school. After various adventures involving ogres and giants, Ella returns home only to find that she's stuck with Hattie and Olive again since Sir Peter has married their mother, Dame Olga. Dame Olga is (rightly, we suggest) irritated with Sir Peter for tricking her into marrying him after he lost all his money, and so she (wrongly) demotes Ella to kitchen wench.
The initial conflict returns, and things go from bad to worse: yup, we'd call this a complication.
Ella survives the nastiness at her stepfamily's hands, in part because she's got Char for a pen pal. He confesses his love for her, which is exciting for like five seconds before she realizes that anyone could use her obedience to get to him as future king. Betray state secrets? Sure! Assassinate the king? Just give me a knife!
She dumps Char by letter, thus reaching the crisis of awful things that her curse has inflicted on her. She can't help deciding to see him one last time at the masked ball his parents put on for him, but he eventually sees through her disguise and once again asks her to marry him.
Caught between Char and her stepfamily, both of whom want Ella to get married to the prince (Char because he loves Ella; her stepfamily so they can benefit from royal connections), Ella has a wee breakdown.
Finally, through her love for Char, she reaches deep within and breaks the curse (which, incidentally, frees her from the nastiness of her stepfamily that had been one of the main conflicts of the book). Now she's free to defy her family like a normal teenager.
After Ella realizes that the curse is broken, she tells off her stepfamily and tells Char that she's able to marry him. Mandy, who's supported Ella all along, confirms that the fairy's curse is gone so Ella can live her life normally. Yay!
Ella and Char are married. She's too nice to punish her stepfamily for being such jerks to her, but they're not exactly the most welcome visitors. Still, they and her father benefit from having royal connections, though, so they also get a slice of the happy ending. Mandy comes to cook for Ella and Char at the palace, and the couple starts a family. Ella doesn't want to be a princess, but is happy with the titles of Court Linguist and Cook's Helper. Now that Ella gets to make her own choices all the time, she exercises that freedom. All the time.