Xia Ruoxin bit another mouthful of the biscuit. It looked like she would not have any returns for today. However, she did overhear their conversation pretty clearly.
If she guessed correctly, it was like this.
Bai Luoyin had always been secretly administering drugs on Gao Yi, and then she used Wei Lan and Bai Zhenfeng going out as an excuse to put all the work—be it real or something that she purposely dug out—on Gao Yi. This would then make Gao Yi busy enough to neglect his health and would think that his deteriorating health was due to him being too tired instead of drugs.
Also, she saw that Gao Yi's arm was wrapped that night. If Gao Yi was like other people who would not notice the difference in their wound—naturally, he would not notice the tiny needle hole there.