Gu Yi Zhong is the young master of the well-known Gu Family in Suzhou. He graduated from a top university abroad with a degree in architecture. During the War of Resistance Against Japanese Aggression, Gu Yi Zhong chose to stay in Suzhou. Although he pretended to be focused on protecting cultural relics, he was actually working secretly to fight against the Japanese.

One day, Gu Yi Zhong is caught up in a dangerous rescue mission and is falsely accused by the Japanese of being a traitor. With no way to prove his innocence, and determined to uncover the real betrayer, Gu Yi Zhong decides to go undercover. He secretly joins the Japanese army and becomes a hidden member of the Suzhou Secret Service. As he navigates this risky mission, he faces danger at every turn.