Boyfriend User Manual

Lin Yijian is a college student and aspiring comic artist who returns home for winter break after a grueling semester. During her early morning flight, she experiences a bizarre phenomenon: a clear male voice begins speaking inside her head, marveling at modern technology like airplane windows and mobile phones as if they were magical artifacts. Initially fearing she is suffering from schizophrenia, Lin Yijian attempts to ignore the voice, but it persists with relentless curiosity about her world. Upon landing and returning home, the voice remains, identifying himself as Li Hui, a general from a feudal dynasty known as Shun. He reveals that he inhabits her mind during moments of sleep or deep relaxation, effectively bridging the gap between his ancient, war-torn reality and her modern, peaceful life.

The core conflict emerges from the stark contrast between Lin Yijian’s mundane concerns and Li Hui’s life-and-death struggles. While Lin Yijian worries about her comic creation and her overbearing but loving parents, Li Hui faces political intrigue and military shortages. He is stationed in Yuding City, where his adoptive father, the Military Governor, and his rival, Commandant An Gongyi, conspire against him. An Gongyi deliberately withholds essential armor and supplies, attempting to force Li Hui into a suicidal battle or frame him for failure. Li Hui’s immediate problem is the lack of protective gear for his troops, which leaves them vulnerable in the impending conflict.

A key turning point occurs when Lin Yijian, initially reluctant to engage, begins to assist Li Hui after he points out flaws in her comic’s armor design. Realizing her knowledge of history and technology can aid him, she researches alternative protective materials. She discovers rattan armor and shields, which are lightweight and can be produced quickly using local materials, unlike traditional iron armor. Li Hui, impressed by her contribution, shares his courtesy name, Weizhao, marking a shift in their relationship from mere curiosity to mutual cooperation. Lin Yijian also introduces him to the Mandarin Duck Formation, a tactical strategy from Chinese history designed for coordinated infantry combat, which Li Hui adapts for his soldiers.

As the narrative progresses, the bond between the two deepens. Lin Yijian learns of Li Hui’s isolation and the political machinations against him, while Li Hui finds comfort in Lin Yijian’s company, which offers a respite from the brutality of war. When Li Hui warns her that communication may cease once active combat begins, Lin Yijian, despite her fear, wishes him safety. This emotional exchange highlights the growing attachment between the modern girl and the ancient general. Meanwhile, Lin Yijian continues her daily life, navigating family dynamics and her comic project, now infused with the secret knowledge that she is indirectly influencing a historical battle.

The story direction moves toward the impending battle as Li Hui prepares to ambush the enemy using the newly acquired rattan shields and the adapted formation. The narrative juxtaposes Lin Yijian’s quiet New Year’s Eve celebrations with Li Hui’s tense military preparations. After a successful ambush that eliminates the enemy vanguard, Li Hui reflects on the peace Lin Yijian enjoys, cherishing the memory of her concern. The relationship evolves into a symbiotic partnership where Lin Yijian provides strategic and technological insights from the future, while Li Hui offers her a connection to a world of honor and duty, fundamentally altering her perspective on her own life and creative work.