Zero Hour

Zero Hour is the the third terran mission of StarCraft II: Wings of Liberty.

Raynor's Raiders prepared to leave Mar Sara with the "liberated" alien artifact. However, they were suddenly besieged by invading zerg. The rebels held out until Hyperion evacuated them.

Zero Hour shares a similar premise to the StarCraft mission, Desperate Alliance, where Raynor flees Mar Sara during the Great War.

Background
The stolen alien artifact was transported by truck back to Backwater Station. The trip was uneventful despite fears of Dominion pursuers. The Raiders timing was impeccable. As they neared Backwater during the night, zerg spores began landing at the abandoned dig site. The infestation spread rapidly to the outskirts of Backwater within an hour. Pockets of terran troops desperately held out in hope of relief.

The Raiders immediately requested support and evacuation from their mobile base and headquarters, the battlecruiser Hyperion. For the second time in five years, Jim Raynor was fleeing Mar Sara in the face of a zerg invasion.

An Old Familiar Feeling
The Raiders were entrenched in a defensible position accessible from the ground by only two bridges. The rebels received regular appeals for help from terrans in the area. The zerg attacked from nearby nests and were reinforced by sacs and nydus worms.

As dawn broke, the zerg made a final large scale push. The Raiders were saved by the timely arrival of Hyperion. The ship finished re-entering the atmosphere nearby and blunted the immediate threat with its weapons. The Raiders had boarded by 06:21.

Gameplay
Building up a strong defense is all that is required to finish the mission. Placing two or three bunkers at each entrance of the base, along with two or three SCVs each, should be adequate. However, to unlock achievements it is necessary to venture out of the base to rescue fellow rebels. Having a large force of marines and medics (20+ combined) is necessary to survive such journeys on harder difficulties.

There are some marines and medics scattered about the map. Rescuing them is an optional objective and they help bolster Raynor's forces. To destroy the hatcheries required for the achievements, keep in mind that Spine crawlers can quickly whittle down marine numbers even with medic support. Always fall back if a zerg wave approaches while cleaning out the spine crawlers to reduce casualties.

Escape from Mar Sara
thumb|left|300px|The Raiders escape the zerg invasion and consider the implications. Hyperion fought through mutalisks to make the warp jump from within the atmosphere. To his horror, Raynor learned the zerg attack was part of a larger, sector-wide invasion. The Queen of Blades was on the move. The Second Great War had begun.

Jim Raynor received a distress call from Agria, but was also given a lead on a job by Tychus Findlay. The Raiders could take one job, leaving the other for later.

Easter Egg
A tauren marine may be found at the upper section of the map near one of the zerg bases. It disappears into a "tauren outhouse" when approached. When clicked several times, the tauren outhouse lifts off and flies into space. This subsequently unlocks the song Terran Up the Night on the jukebox aboard the Hyperion.