That sequel is written for Schermionie birthday! It's un-beta'ed, but I did my best with it. I hope you'll enjoy it, Schermionie!
Since Tom had rescued Myrtle she had stalked him everywhere. First he was annoyed, but he rapidly understood it could be useful. Tom knew that Dumbledore was watching his deliveries very closely since last year. But he needed to have those books enter Hogwarts. Without the headmaster control. And Myrtle was the perfect solution.
He started with having her receiving the packages by owl. No one would suspect a first year receiving large boxes by owl, expecting it was from their parents.
He did not trust her with important things at the beginning, the first package were fakes. But soon he knew she was blinded with love and naïvety: they were no risk.
Myrtle had accepted the offer very quickly, without thinking or asking questions. She had to meet him secretly to give him the boxes and it was enough with her. The first year girl was crazy about him, and it served Tom well.
She had been his mailbox for months before he assigned her new tasks. Covering up his missed Slughorn's parties, for example. She had to lie to the professor and say he was tutoring her when in fact he was working on a task.
Myrtle happily obliged all requests made by the handsome boy. They had a special link, she thought. And it went like that until the end of the year.
During the holidays, Myrtle was disappointed when Tom never sent a letter. But his charming smile and request for help back at Hogwarts were enough to make up for it.
Tom re-won her trust really quickly and their little routine continued through her second year.
However, that night, he couldn't find her to cover his new escapade to the Chamber of Secrets, but he went anyway. His self-confidence had grew during the last years, he was sure nothing could happen.
Tom wasn't aware of the crying girl in the cubicle and opened the Chamber. The Parseltongue incantation was delightful to hear, but that time a yell interrupted him: it was Myrtle, crying.
She probably hadn't recognized him and yelled to him to go away. The girl was gesturing toward the exit when she finally recognized him and launched herself at the only boy who never mocked her.
Tom was disgusted by her attempt and stepped backward. The Basilik he had conjured was now in the bathroom and the sight of it made Myrtle go away. She wasn't yelling from anger anymore, but from fear. Tom spoke to the snake. The animal was coming near her and she understood that Tom wasn't trying to help her like she first thought. He was ordering it to kill her. The fear and betrayal Myrtle felt had been furtive, in one glance, she was dead.
Tom looked at the girl body on the floor with a smile. Mudbloods could be rather helpful sometimes, and Myrtle had been a nice tool.
He sent back the Basilik inside the Chamber and with a quick last glance toward the corpse on the floor, he left the bathroom more happy than ever.