The plane is flying at high altitude. A passenger, Wang Qi, insists on making a phone call, but suddenly suffers from cerebral edema and dies despite efforts by the flight attendant Li Xiaowan (played by Fu Jing) to stop him. The deceased, Wang Qi, was a researcher in a confidential unit, suspected of stealing confidential files for overseas transactions. The National Security Bureau sent an investigator, disguised as his younger brother "Wang Hao" (played by Sun Honglei), to infiltrate, and dispatched Mai Tian to rendezvous with "Wang Hao", aiming to catch the criminals all at once.