During the Lantern Festival, people prayed for Empress Wu Zetian. A monster with its whole body bathed in fire appeared inexplicably. Witnesses claimed it was a "fire-bathed unicorn". It is said that eating unicorn flesh and blood raw can cure all diseases. Wu Zetian immediately ordered Xue Xin, the Minister of Dali Temple, to find out the truth within seven days. The young Di Renjie came to Chang'an City and was promoted to the "Temple Secretary" of Dali Temple. As a result, he learned about the strange case of the Lantern Festival and he had to wait until the case was solved before he could report on his work. Di Renjie, who wanted to wait for his report on his work honestly, was itching for this bizarre case and was involved in the case by mistake. After some investigation, Di Renjie finally found the so-called "fire-bathed unicorn". It turned out that the grandson of the old prince Li Huai had a strange disease and was covered with hard silver psoriasis, like a monster with scales. However, the truth of the matter was not that simple. Di Renjie was disliked by Xue Xin for his unauthorized actions, and was not allowed to report on his work, and was driven back to Bingzhou. Before leaving Chang'an, Di Renjie connected all the doubts and found that the instigator was Xue Xin, the Dali Temple Minister. Just when Xue Xin was about to succeed in using the young prince to assassinate Wu Zetian, Di Renjie arrived in time and successfully stopped his conspiracy.