There is a VC propaganda squad operating in the area. They slip across the border from Cambodia and terrorize the local villages. Guarded by a company of NVA they are acting with impunity. Mack Gerber wants to put a stop to them. For that he will need helicopters to insert his men quickly before the Cong can slip across the border.
The third book in the series is another exciting entry. This explores the beginnings of using helicopters in the war to move men quickly in an inhospitable country. This was a crucial component in fighting the war in Vietnam. Also we are shown the casual brutality of the VC. They massacre a village after the Green Berets successfully ambush them during one of their propaganda speeches. The VC didn’t want word of the humiliating defeat to get around so they destroyed the village. They would do this several times throughout the series. They also show the presses total lack of any interest in such incidents because they are so common. A very cynical and callous policy the VC waged.