The incident of the detention of the four spies that Emma and her friends sent occurred a few days ago. And both encounters between Emma and Levi happened after that event. Now, Emma understands why Levi's behavior felt strange. It's because Levi already knew that Emma was his enemy. Emma is the figure behind the Black mask.
Levi pretended to be clueless. He bought ice cream for Emma, caressed her cheek, and made her smile. All of these things the man did when he found out that Emma was the one causing his business to collapse.
Their conversations replayed in Emma's mind. Everything Levi said in their last two meetings were words he uttered when he knew that the girl in front of him was Black.
"He knows it's me... and he's still going to destroy me," Emma uttered in her mind.
"Emma. Emma." Calvin gently shook the girl beside him after calling her multiple times but getting no response.