Gu Beichen is a decorated regimental commander in the military district who has spent the last four years searching for his wife, Lin Su, after she mysteriously disappeared. Despite their deep love and plans to marry, she vanished without a trace, leaving Gu Beichen emotionally detached and functioning like a walking corpse. During a routine mission to protect a female translator at a military airport, Gu Beichen intercepts sniper fire and shields the target with his body. Upon looking into her eyes, he recognizes Lin Su, who now goes by the alias Comrade Gu and treats him with cold indifference. She rejects his attempts at intimacy, addressing him formally and wiping her hand after he tries to shake it, which devastates Gu Beichen.
Lin Su is revealed to be a brilliant translator with a photographic memory, capable of converting written descriptions into precise technical sketches and identifying errors in complex models. She was recruited to a secret research base in the Northwest to translate critical documents for a national project. Her past is marked by tragedy: after Gu Beichen left for a mission, she discovered she was pregnant, only to have her mother die in a laboratory accident. Left alone and abandoned by Gu Beichen’s silence, she raised her child in hardship, hardening her heart to survive. She hides a child’s drawing labeled “Mom” in her book, a secret that triggers Gu Beichen’s jealousy and fear that she has moved on.
At the base, Lin Su faces prejudice from senior engineers who doubt her capabilities due to her youth and gender. However, she quickly proves her worth by correcting a critical calculation error in the project’s fluid dynamics model, preventing a potential structural failure. Her expertise earns her the title of chief technical advisor. Meanwhile, Gu Beichen, assigned as her security detail, struggles with his feelings of rejection but remains devoted, bringing her food and a handmade desk lamp to protect her eyesight during late-night work. Their interactions are tense; Lin Su maintains emotional distance, fearing vulnerability, while Gu Beichen patiently tries to reconnect.
The narrative shifts when a computer system crash reveals a malicious backdoor left by an enemy agent codenamed “Mole.” Lin Su suspects a senior researcher, Professor Qian Siming, based on logical inconsistencies in his work and patterns from her late mother’s notes. She and Gu Beichen form a strategic alliance to catch the spy. Lin Su plants a trap in a modified algorithm, and when Qian Siming attempts to reverse-engineer it, he triggers an alarm. Surveillance confirms he is communicating with an organization called “The Shepherd” via shortwave radio. Gu Beichen’s team apprehends Qian Siming, who confesses to espionage, initially motivated by concern for his son abroad but later corrupted by financial rewards. The confession reveals that “The Shepherd” is specifically interested in Lin Su’s mother’s notebook, which contains secrets related to “Project Dawn.” The story ends with the immediate threat neutralized, but the larger conspiracy and the emotional rift between Gu Beichen and Lin Su remain unresolved.
