Manipulated. That's how Tom Marvolo Riddle felt, sitting in the Chamber of Secrets, his mind going over the events of the past 24 hours. The lies, the friendly grandfather facade, The manipulations.
Betrayed. That's how he felt when he saw the person who he thought he had loved sitting in the office of Albus Dumbledore, telling the Deputy Headmaster of Hogwarts School of Witchcraft and Wizardry that she was getting fed up of being with him.
Tom Riddle knew that he had been manipulated by a master when he saw her in the office of the Deputy Headmaster. Grisha McLaggen, the girl that he had loved. The Heir of Gryffindor, a key part of a plot by the Transfiguration Professor, asking her mentor for more of a potion that would effectively control him.
'This cannot happen. Never again.' the future Dark Lord thought to himself. 'There again, Dumbledore has always taken more than a normal interest in me ever since he found me at the Orphanage.'
Thinking back to the past year, he wondered about how he had found out about his heritage as a member of the Gaunt family, how he was the Heir of Slytherin, how he could speak Parseltongue and how he had fallen for Dumbledore's manipulations.
It was all because of Grisha McLaggen.
She, along with Albus Dumbledore, was the only two people who knew about his group of followers, mere servents in his mind. Grisha was the one who pointed him towards certain books in the Restricted Section and she was the one who got his mind obsessed with the Chamber of Secrets and Horcruxes, his path to immortality.
Walking around the Chamber, he knew he had yet to find its full secrets, and how he could harness those secrets to gain his revenge.
'Grisha McLaggen will pay,' the Heir of Slytherin decided, 'She will pay eventually, with the rest of the Wizarding World following in her footsteps.'
Stepping towards the giant bust of his ancestor, he said the words which would unleash the beast beyond it.
"Speak to me, Slytherin, greatest of the Hogwarts Four"