Bring Kiko and Tang Ren (except Hao Feng, they are all friends)
There is a complete case
You may use some chemistry and optics content. It is said that if you learn mathematics, physics and chemistry well, you will not be afraid of traveling all over the world (bushi)
"Phenylethylamine is the hormone of love. Do you want to spend the rest of your life deciphering my perfect crime?"
Purpose: Grow through cases