When Mo Tingshen came back up, Mo Li was no longer in her original spot. He took the cup into the study, and indeed, Mo Li was inside. They chatted for a while before Mo Tingshen left.
Just as he returned to his room, Chu Yao called.
He spoke with her, changed his clothes, and before taking a bath, he let her know and placed his phone on the bed. After he finished bathing and came out, the call was still ongoing.
"Go to sleep, I'll leave the speaker on."
Mo Tingshen remembered that that night, Chu Yao didn't say anything on the phone; even her breathing was very light, suppressed, indiscernible whether she was crying or not.
Now that he thought about it, she must have encountered something terrifying that night.
Perhaps, it was then that Mo Li developed feelings for her.
She was seeking his help.