From late June 1970, the 7th Marine Regiment had been rotating reinforced rifle companies on 5-day patrols of the area, which regularly uncovered PAVN/VC positions and engaged in small skirmishes.

The plan called for an intensive air and artillery bombardment intended to drive the PAVN/VC into shelters allowing the 2/7 Marines to land at 12 separate landing zones, the 1st Platoon, Company D, 1st Reconnaissance Battalion to establish 3 observations posts, and for the mortar battery of 3rd Battalion, 11th Marines to establish a firebase on Hill 845.

[1]: 92 On 5 September, Company E pursued a PAVN soldier into a cave in a ravine near LZ Vulture and were met by heavy weapons fire.

[1]: 111 On 18 October, the 1st Marine Division ordered a change to the operation with six-man patrols deployed in the Quế Sơn mountains which would call in a quick reaction force (QRF) at LZ Baldy to exploit any contact.

On 26 October, the QRF discovered an abandoned battalion-size base camp, and on the same day two reconnaissance teams ambushed 10-15 PAVN north of LZ Rainbow killing five.

[1]: 113 [2]: 232 On 5 November, Company B, 1/5 Marines found an abandoned base camp and documents including the files for the VC security section in Quảng Nam Province identifying leaders and agents.

[1]: 113 On 18 November, a HMM-263 CH-46D which was extracting a reconnaissance team by McGuire rig crashed into a mountainside in bad weather 3 kilometres (1.9 mi) southeast of LZ Rainbow, killing all 15 Marines on board, including the Reconnaissance Battalion commander Lt. Col. William G. Leftwich Jr.[1]: 114 On 19 November, a newly formed Republic of Korea Marine Corps (ROKMC) Marine reconnaissance unit joined the operation establishing a base in Hill 322 in the northeast Quế Sơn mountains and they would be joined by the 6th and 7th ROKMC Companies later that month.

Companies K and L searched the caves and discovered a major PAVN/VC command post including three radios, three generators, spares and other equipment which were believed to be part of the elusive Front 4 Headquarters.

[1]: 217 On 25 January, 2nd Platoon, Company L, 3/5 Marines engaged 10 PAVN 2.48 kilometres (1.54 mi) northeast of Firebase Ross, killing nine for no losses.

On 15 February Companies K and L, 3/5 Marines were withdrawn to Hill 34 (16°00′07″N 108°10′12″E / 16.002°N 108.17°E / 16.002; 108.17) near Da Nang Air Base for redeployment to the United States.

[1]: 244 This article incorporates public domain material from websites or documents of the United States Marine Corps.