The Big Dipper Division is a mysterious organization under the Imperial City Division in the Northern Song Dynasty. The members are all code-named after the Big Dipper Stars, and each has different abilities. At the time it seemed miraculously advanced technology. As the personal guard troops directly under the emperor's orders, they are a barrier to protect the court and the common people in the world. Among them, Tai Sui, a reckless boy with the name of "immortal body", accidentally met the violent loli Wu Yaoguang with supernatural powers and the romantic Liu Suifeng, and followed them to join the Beidou Division
Tai Sui and his partners have repeatedly solved strange cases, punished evil and promoted good. Through a series of cases, Tai Sui gradually discovered that his "immortality" was related to his confusing life experience, and there were even bigger conspiracies behind these cases. He is unwilling to join forces with evil forces, and uses loyalty, friendship and wisdom to unite his partners and grow continuously. In the end, with the help of the righteous people, they finally found out and punished the original culprit, helped justice and benefited the people. Tai Sui also finally found his lost family and reaped a beautiful love.