On the planet Char, terran forces under the command of Sergeant Bama Kowalski were under attack by the armies of Amon. Allied forces were sent to relieve her. However, they had to deal with void thrashers that were sieging her base. As the battle began to turn in the favor of the allied commanders, Moebius Corps sent an Archangel to support Amon's forces.
The mission has the players' bases in the southwest side of the map, with Sgt. Hammer's base situated in the corner behind them. The players must battle their way across the map, destroying the void thrashers that get in their way. If Hammer's fortress is destroyed, the mission ends.
The two expansions are quite far from the main base, and their entrances besides the ramp into the main base are directly guarded by enemy units. Players should clear out these areas shortly after taking their expansion, to allow their units to move about freely. The long distance between these bases makes automated defenses useful to hold off enemies until the main army can arrive to defend.
The first void thrasher will spawn at 4:30 into the game. The second wave spawns at approximately 9:30, the third at 13:30, and the final wave at 18:00. Approaching a void thrasher's spawning point will cause it to appear regardless of time. The void thrashers will attack Sgt. Hammer's base until attacked, at which point they turn their attention to fighting the player forces. An important note is that the next wave of void thrashers will still spawn regardless of if the last wave has been killed or not; if the players wait too long, more and more thrashers will be attacking at once and Sgt. Hammer's base will quickly be destroyed.
As a bonus objective, at 14:30 (or when the player forces approach the area), an Archangel will spawn among an enemy force behind the spawning point of the third wave of void thrashers. When the Archangel spawns, players have eight minutes to reach and destroy it, or else it escapes. When the Archangel takes heavy damage, it will transform into fighter mode and fly to the northern part of the map, where it will initiate auto-repairs. The Archangel can be shot down by anti-air fire as it flies away, and will not flee when engaged the second time. Destroying the Archangel awards bonus experience.
The following mutators have been applied to Void Thrashing.
Hammer's fortress was moved from its original location during development, in order to be located behind players' bases.