The campain can be sum up the this quote from Starcraft II The Wings of Liberty.

“Tychus Findlay: So how was it, Jimmy, fightin’ them zerg?
Jim Raynor: All the scrapes we got into back in the day, all the narrow escapes, none of it compares to how terrible they are, Tychus. You don’t know what true fear is till you’ve got a thousand of these sons of bitches barrelin’ down on ya.”

—StarCraft II, conversation prior to Zero Hour.

-http://tvtropes.org/pmwiki/pmwiki.php/Quotes/ZergRush

You and few of your friends have to hold out against the Zerg, long enough to complet the missions. However will it be easy?

Chased down by the Zerg, you and your companions barely make it to extraction point. But you see the dropship going down with flames.

Fast Pased, Full of Actions, the untold stories are waiting.

Starcraft Heroes

XakAni