The film states that Japanese forces went into action because Chinese forces "illegally opened fire." Japanese forces held themselves back, asking the Chinese forces to respect the cease-fire agreement, but the Chinese unilaterally violated the agreement. The Imperial Army thus decided to "punish" China, and quickly occupied Wanping and other areas.
影片的內容指出，日方出兵是因為在蘆溝橋上，中國人對其「非法射擊」，日軍一忍再忍，要求中國軍遵守停戰協定，但中國片面毀約，於是皇軍決定「嚴懲」中國，不一會兒功夫即佔領了宛平等地。