While Voldemort had been immersing himself in the Dark Arts, Nagini was studying other things. Ever since last year, when Professor Dumbledore told the class about animagi, she had been fascinated at the idea about being able to turn into an animal. She had never tried with just her magic and feeling her way around like she did with everything else, afraid she could do something wrong.
Her information wasn't as hard to find, but she had used up all last year just to figure out how. The witch or wizard had to know themselves well enough to know what kind of animal they might be. They always had a little bit of a choice as to what kind of animal. It was the only thing holding her back at this point. Once you chose your animagus, it was permanent.
She was staring at the cover of her book thinking about this when Voldemort came in.
"Hello, I wanted to speak to you about something," he said, glancing at her book. When she looked up, he motioned for her to follow him.
They went out the common room and into one of the unused dungeons. "Lumos," Voldemort prompted. Nagini attempted the same but her wand only flickered and the light died. She gave an exasperated look at it and it immediately lit up again.
Voldemort disregarded her wand and said "Have you ever heard of the Chamber of Secrets?"
A sense of foreboding crept upon Nagini, "No…"
"As you know, when Hogwarts was first founded, the four founders disagreed on who they wished to admit into the school. Despite these disagreements, three of the founders were as close as ever, but Salazaar Slytherin was not. He grew apart and before he left, it was rumored that he built a secret chamber deep under the school and put a monster down there. Only the true heir of Slytherin could open it and purge this school of those unworthy to attend."
"You," she whispered.
"Naturally, however, I've been having trouble find it. I just want you to keep your eyes open for any clues."
She nodded. He was nearly out the door when she finally pulled him back. "Wait, I was just wondering if you could help me with something."
Voldemort waited for her to continue. "I was trying to figure out what kind of animal I would be if I was an animagus."
"A snake," he answered, then gave a strange hiss that she could not make out and left.