Gangcheng security investigation operative Lu Mohan and Su Wanyin once promised to walk toward the future side by side, but were unexpectedly separated due to a mission. Three years later, upon reuniting, identity mysteries and misunderstandings led the two to make new choices. As the truth unfolded, they learned trust and responsibility from suspicion, joined hands to cooperate in a joint investigation, submitted crucial evidence, and protected personnel safety to evacuate. Facing crisis, the two held their bottom line and also understood that true love is not control, but respecting choices and bearing burdens together, guarding each other and justice through hardships.