Apparently walls in Yangs’ house are incredibly thin, because Katie heard Wendy and Lucas in kitchen, downstairs. She run upstairs, then through badly placed rooms until she reached Wendy’s bedroom. Luckily Wendy and Lucas were fully dressed because she didn’t think she could have handled a view of elders’ naked bodies.
Katie: You! You… cheater! You stole my first kiss with another woman and now you… you are playing with some old man?
Wendy: Firstly, Lucas isn’t some old man, he is my old man. Secondly, it was you who had kissed me, not the other way round. And finally, didn’t we agree to put it behind us? So stop making a commotion and go back to Maribel, I can hear her crying.