Lu Junran traveled to the future and was displeased by his mother-in-law, who was a natural mermaid. Unexpectedly, at the age of seven, he discovered that he was actually a more noble deep-sea mermaid. In order not to become a glass doll, he worshiped the venerable Caesar as his master. From this, he began to fight openly and secretly with his master's rival disciple Augustus, and the entanglement of grudges...