Time Travel: Assassination of Wu Zetian

The protagonist is a high school chemistry teacher in the 21st century, and his son is an ordinary boy under the age of fourteen. The two traveled together to the period of Wu Zetian. After traveling through time, his son became the emperor's grandson Li Chongrun. According to historical records, Li Chongrun was sentenced to death by Wu Zetian for making false remarks about Wu Zetian's male favorites, the Zhang brothers. The protagonist can do anything to save his son, even assassinate Wu Zetian.