After the glassing of Chau Sara by the protoss, the Terran Confederacy assigned a new magistrate to the planet's sister world of Mar Sara. An adjutant informed the new magistrate that an equipment demonstration had been prepared at their convenience.
The mission is a simple tutorial exercise to instruct players in base building and producing units. If the player ventures out from the base, they may encounter zerglings, but they possess no real threat.
The Nintendo 64 version of StarCraft has a more complicated tutorial, split over two missions (the second called "Officer Training"), both of which take place on the surface of Mar Sara. A single marine was dropped off via dropship and found a few more marines; they fought a number of Sons of Korhal forces scattered in the area. They received an urgent summons to a nearby undefended command center that was under attack by a small Sons of Korhal force; the colonial marines won this encounter, and also fended off a small force of rebels who arrived via dropship. In Officer Training, the Magistrate trained a force of marines and firebats and had them attack a nearby Sons of Korhal base, destroying it.