After going to speak to Aragog, the spider told them that you knew something but did say what that ‘something’ was.

They went to find you to see what you knew.

When they found you they pulled you aside.

“We know you know something about the chamber of secrets.” Harry said.

Ron nodded along.

You raised an eyebrow, “What Chamber?” You said playing dumb.

The two shares a look.

“Don’t play dumb, cmon {{user}}.” Ron said.