"I'm just an old broody."
—Aunt Finny, The Capture, page 37
When Soren and Gylfie were taken to St. Aggie's, Soren was placed with Finny as his pit guardian. She gave out numbers to all the owlets who fell under her care. Finny numbered Soren as 12-1, claiming it was a very special number, and had a peculiar way of treating the owlets that she attended to. She insisted that they call her "Auntie" and would often give them extra rations of food and even allow them to ask a few questions: an action that was greatly discouraged at St. Aggie's. Soren was no exception.
Later, after Soren's feathers were plucked out during laughter therapy (he had accidentally asked a question), Auntie and Hortense took care of him afterwards. She asked him if there was anything she could do and he asked her to tell him about the legends of Ga'Hoole. To this demand, she seemingly shrivelled with fear and fainted.
Then her true nature was finally revealed when she, along with Skench, Spoorn, Jatt and Jutt caught Hortense smuggling eggs out of St. Aggie's with the help of the two bald eagles, Zan and Streak. A battle ensued in which Auntie threw Hortense off the cliffs to her death. She snarled her satisfaction after she had done this. It was during this battle that she was scarred by one of the eagles across the throat. The scar darkened, making her once white feathers darker than normal.
The band, along with the rest of the chaw of chaws, returned to St. Aggie's where they saw Aunt Finny again and found out that she had been promoted to an eggorium supervisor. Her scar had healed, but one of her eyes was cloudy, and wept continuous tears. Soren notices that she smell oddly like eggs. She permitted Soren and Martin to work as moss tenders. Ruby revealed to them that Finny often came up to the hatchery and was an egg eater. When she recognized Soren, she chased after him as he tried to escape, but was stopped by Twilight. She also recognized Gylfie, and was about to kill her, when Soren opened up the scar in her throat, killing her.
When Soren first met Finny, he thought she was the best owl of all of the St. Aggie's owls. She acted very sweet to Soren and his pit mates, giving extra tidbits of food, permitting them to ask questions, and allowing them to sleep in tiny crevices of the canyons if they ever had trouble sleeping.
However, all of this was just a cover, hiding a truly dangerous, murderous, and mentally ill owl. When the chaw of chaws went to St. Aggie's, Finny seemed to be suffering what seemed to be a severe depression, but despite this, she would still act kind to the captured owls. It is revealed that Finny was also a cannibal, sneaking into the eggorium, stealing and eating eggs and newly hatched owlets, much to the horror of the chaw of chaws. She was also a very dangerous fighter, nearly killing Soren until Gylfie recited the legends of Ga'Hoole.