Henrietta is the cousin of Henry, the daughter of the sixth son of Amram, Francis. Her mother is Dorothy. She is the second oldest daughter, the oldest being Penelope and the youngest, Anastasia. She goes through the cupboards on many occasions. She caught Henry looking at the cupboards and uncovered them along with him. She has a long time desire of being sucked up by a tornado in the right circumstances.
She appears in all of the books.
In the first book, she uncovered the cupboards along with Henry and opened the door to Endor, and peering inside. She was almost pulled in, but Henry came and saved her. She also chased after Eli FitzFaeren, which led to her being stuck there as the cupboard closed up behind her. In the end, Henry came to rescue her and they witnessed the hauntings. When they got back, Nimiane, the witch-queen of Endor, had already entered the house and they helped to strike her unconscious. Then Henrietta helped in pushing Nimiane's body into a random cupboard, which actually led to Carnassus.
In the second book, she dug up the key with Henry, which she had buried with the intention of being free to secretly roam through the cupboards. Henrietta then helped Henry back to the house when he was burnt by a dandelion. (And then he was brought to the hospital because they thought he’d been struck by lightning.) Henrietta decided to explore a random cupboard and went into the cupboard named treb/actium/constant. She was nearly killed in the sea battle through that cupboard and got covered with grime. When Henry came back, she heard that he and Richard were planning to go through the cupboards to find Eli, because Henry thought he would know who his parents were. Henrietta went through the cupboard to follow them, but in actuality, they had been kidnapped through the cupboards by a powerful wizard called Darius. So she got captured by two FitzFaeren instead and talked to their Queen. But Henrietta managed to escape, and, with Eli, started to make her way to Hylfing, her father's birth place. On the way, they were met by Caleb, Henrietta's uncle. He helped her and Eli on their way to Hylfing. They arrived shortly before her cousin Henry did. When the witch attacked the city, Henrietta helped retrieve the arrow of Ramoth Gilead. Caleb succeeded in killing Darius with it.
In the third book, when the emperor's soldiers come to town, she puts up too much of a fight and is thrown into her family's burning home. This leads the rest of her family to believe she was burnt alive. But Henry was watching and he went into the house and rescued her and their Grandmother Anastasia. Henry takes her and their grandmother through his cupboard back into Kansas. They recruit the help of Zeke and Antilly Johnson, taking Zeke with them to Endor to find Mordecai and Caleb and leaving Tilly to care for Grandmother. In Endor they find themselves in the tomb of Nimiane and her sister Nia, where the witch-queen was imprisoned for so many years. Coreden, (and later more fingerlings,) follow them through and they barely escape, climbing through the tombs all the way up to a bell tower, taking the cupboard with them. Henry, Henrietta, and Zeke strike the bell and scare off their pursuers for a moment. Henrietta and Zeke then travel back through the cupboard to the attic, leaving Henry on the other side, carrying the cupboard. When they come back out, they find themselves in Nimroth’s library with Henry and learn that he found his father, Mordecai, and Caleb. They dump as many stacks into the attic through the cupboard as they can until Coraden gets into the library from a backway past Modecai and Caleb and grabs Henrietta by the hair. She tries to get Henry and Zeke to leave her, but they refuse and fight Coreden. Henry cuts Henrietta’s hair, freeing her, and they escape through the cupboard. They burn it behind them and go to the Horned Horse, an inn in Hylfing where they wait to meet the two brothers. When Henrietta wakes up the next morning, Henry is gone and she and Zeke are captured by Nimiane's fingerlings, who are looking for Henry. They are brought to the city of Dumarre, where Nimiane is, and are put in cages in her throne room. She then witnessed Henry defeating the witch queen there.