During an escort mission Major (then Captain) Pless monitored an emergency call that four American soldiers stranded on a nearby beach, were being overwhelmed by a large Viet Cong force.  Major Pless flew to the scene and found 30 to 50 enemy soldiers in the open.  Some of the enemy were bayoneting and beating the downed Americans.   Major Pless displayed exceptional airmanship as he launched a devastating attack against the enemy force, killing or wounding many of the enemy and driving the remainder back into a treeline.  His rocket and machine gun attacks were made at such low levels that the aircraft flew through debris created by explosions from its rockets.  Seeing one of the wounded soldiers gesture for assistance, he maneuvered his helicopter into a position between the wounded men and the enemy, providing a shield which permitted his crew to retrieve the wounded.  During the rescue the enemy directed intense fire at the helicopter and rushed the aircraft again and again, closing to within a few feet before being beaten back.  When the wounded men were aboard, Major Pless maneuvered the helicopter out to sea.  Before it became safely airborne, the overloaded aircraft settled four times into the water.  Displaying superb airmanship, he finally got the helicopter aloft.  Major Pless' extraordinary heroism coupled with his outstanding flying skill prevented the annihilation of the tiny force.