When Belle gave birth to her and Toby's baby, Toby had recalled the ancient naming ceremonies of his native land and had convinced Belle to allow him to take the baby girl and name her the way that his own father named him. And so she had relented and Toby decided to name the baby "Kizzy", which phonetically matched a word in his native tongue that meant "stay put" - a nod to his rebellious nature to run and his wife's wish for their child not to do so, but to "stay put" and not leave them (whether on her own or by sale by their owner). And now it is 16 years later and the teenage Kizzy is still there with them, working alongside them on the farm.
The plantation is abuzz with news about the impending arrival of Dr. William Reynolds' "niece", Missy Anne Reynolds, who they had not seen since she was a child. However the talk is not so much about what she has done over the years since they last saw her, but about the scandal that she represents. I.e., it was presumed that Missy Anne was actually the daughter of the good doctor after his obvious affair with his brother John's wife.
Kizzy is excited the most because while growing up, she was allowed to be Missy Anne's playmate and had been permitted to spend a lot of time with her. However during their early years together, Missy Anne had done something that was not only unthinkable, but illegal when it came to slaves - she had taught Kizzy how to read and write. Belle and Toby were aware of this and constantly scold Kizzy for openly displaying her literacy. However Kizzy is also well-grounded in her father's Mandinka culture and makes no bones about discussing that either.
The day arrives for Missy Anne's grand return and Missy Anne, now a mature young woman, invites Kizzy up to her room and they trade stories regarding what had transpired since they were last together. But the conversation is dominated by Missy Anne and her somewhat exaggerated tale about a courtship being carried out by a young gentleman suitor based on a letter he wrote to her. As the daughter of landed gentry, Missy Anne is raised with a certain amount of wealth and experiences befitting her family, her mannerisms begin to grate on Kizzy - particularly when her tale about her father's family and the village griot, is dismissed by Missy Anne as nonsensical. But she shoves her misgivings aside because she has missed her friend. Missy Anne eventually makes Kizzy swear that she won't tell anyone about her male suitor and she even pulls out her family bible to have Kizzy swear on it and Kizzy complies.
Missy Anne then decides to revert back to childhood again, opening the bible, and asking Kizzy to read from it. Kizzy initially refuses, recalling what her parents warned her about, but eventually gives in and starts reading aloud. Suddenly Dr. Reynolds enters the room while Kizzy is reading; startling both and forcing Missy Anne to nervously try to explain away the incident by calling it a "trick" that Kizzy was going to play on her mother Belle. Dr. Reynolds is highly suspicious of that explanation, but files it away and instead scolds Kizzy about wanting to deceive as fine a woman as her mother Belle.
Once Dr. Reynolds leaves, Missy Anne promises that she would always look out for Kizzy to make sure that nothing happened to her. She then announces that she wants Kizzy as her own personal slave, ensuring that they would be able to spend more time together. She even drafts up and gives Kizzy a traveling pass that authorizes slaves to be on the road by themselves by order of their owners, so she can come visit Missy Anne once she returns home to her family at John Reynolds' plantation.
Later back in their cabin, Belle and Toby continue to warn Kizzy about what happens to such friendships between owners and slaves -- or better, between the 2 races, and how culture forces the relationships to change. However Kizzy innocently denies this could ever happen to her. What softens the circumstances for her parents is Kizzy's interest in a young man named Noah who resides on the same plantation. Both Toby and Belle are fond of the quiet and dutiful young man who has been courting their daughter, although Belle senses that he is very much like her husband - rebellious and itching to run away - and Belle's perceptions prove to be true.
Noah eventually comes to Toby and tells him of his plan. He is looking for advice from Toby since he had tried to run twice before and failed. This alarms Toby and he vociferously tries to talk Noah out of it. But once he senses that the young man is deadly serious, he eventually relents and gives him some advice. Noah then lets Kizzy know about his plans and she also protests, however she decides to give him something that she knows will help assure his success at escaping.
Noah eventually heads off and almost a week passes with no word of whether he had been captured, which was generally a good sign. However Dr. Reynolds has hired professional slave-catchers and they eventually find Noah and drag him back to the plantation, chained behind a horse while his mother collapses in horror and Toby, Belle, and Kizzy cower in shock. Noah is taken into the barn and whipped until he reveals who helped him.
Reynolds then calls for Toby and Belle and gives them a lecture about disobedience and the consequences of it. He then tells them that their daughter Kizzy had been implicated in forging a traveling pass for Noah and such transgressions would not be allowed to stand unpunished. Finally he announces his plans to sell Kizzy to a neighboring plantation. This news hits Belle like a ton of bricks and she and Toby immediately begin pleading for mercy - punishment for themselves, whipping of their girl - anything that would not take their Kizzy, their little girl named "stay put", away from them. Their pleas fall on deaf ears even after the once proud and strong-willed Belle gets down on her knees to beg. Then they suddenly hear Kizzy cry out and they realize that the deal was already done, and a wagon was leaving with her in it. They run outside and fall to the ground as they watch their child being taken away forever.
As the wagon passes, Missy Anne hears Kizzy's cries from inside the safety of the house and she begins to nervously and affectatiously denigrate Kizzy in front of Dr. Reynolds. Her doing so allows Reynolds to not only confirm that Kizzy could read and write, but confirm who was to blame for teaching her. However his familial ties keep him from punishing his own (daughter) niece, and in any case, his problem had now been taken care of with the sale of Kizzy to his rather uncouth lower neighbor Tom Moore.