Time travel to become a hedgehog.
No spoilers, but it's true.
To sum it up, thirteen words.
"Time travel, cultivating immortality, love triangle, vulgar plot"
The evil king said, little hedgehog, I want to hold you, but you always turn your soft front to others and give me a back of thorns. Even though I know that, I still want to hug you. Even if my hands are covered with blood, I will not tell you. That is the last thing I can leave to you.
Su Xiaomin loves to sing Wen Lan's Hedgehog, as the lyrics say, "I think I'm not that strong. In fact, every girl is the same. They long for the good love and want to be hugged, but they are afraid of being hurt by love. I admit that I am not that strong, but I am just trying to be strong again and again... The strength of the hedgehog is all an illusion."