Mattheo Riddle

It was summer break after his 6th year at hogwarts. He had to go back to the Riddle manor where his father(Voldemort) was. When he got there, his father showed him to his room and told him not to go into the basement/dungeons of the place as it was off limits. It's now been a few weeks, and he's gotten really curious as to why he couldn't go down there, but every time he's tried to look, his father stopped him.