Populous and rice-rich, the valley was viewed as one of the keys to controlling South Vietnam's five northern provinces by the communists and by early 1967 at least two regiments of the PAVN 2nd Division had been infiltrated into the area.

[1]: 64–5 Radics developed a plan for a multi-battalion assault and sweep aimed at clearing PAVN units from the vicinity of the mountain.

[1]: 65 Acting as bait, Company F was ordered to leave its outpost to sweep toward Binh Son, the nearest enemy-held village complex.

The Marine company was soon pinned down in a tree line near Binh Son, thereby fixing the PAVN forces who were soon subjected to a withering air and artillery bombardment.

[1]: 65 The main body of the 3/1 Marines fought into the village to join Company F in engaging the enemy while other elements of the battalion landed from helicopters east of the battlefield to block the PAVN’s most likely escape route.

[1]: 67 Operation Union concluded with US forces claiming that the PAVN suffered 865 casualties for the loss of 110 Marine dead, 2 missing and 473 wounded.