The story for Wc1 and its add-ons? Here we go:
In Wc1, you, a 2nd Lt., are assigned to the TCS Tiger's Claw in the Vega sector. First you defend some Terran systems against Kilrathi attacks and later on, Confed is staging an attack to drive the Kilrathi out of Vega. You accomplish this by destroying their HQ in the Venice system. Of course you have to battle through various systems to get there and you get the prototypes of the new Rapier for testing as well.
SM1: The Claw (and you onboard) are transferred to the Goddard colony in Deneb sector/quadrant because every communication with the colony has stopped. You arrive there and learn that the Kilrathi have tested a new weapon against the colony, mounted on a ship named Sivar, capable of completely destroying the colony with a single blast. You then follow the small Kilrathi strike fleet back into their territory, destroying the fleet one by one until you finally destroy the Sivar and return to Confed territory.
SM2: The Confed just made allies with the bird-like race of the Firekkan and the Tiger's Claw serves as honour guard. But then massive Kilrathi forces begin to pour into the system and they take the planet Firekka while the Claw retreats. After the defection of a Kilrathi cruiser, under Ralgha nar Hhallas aka 'Hobbes' you learn that the Kilrathi have chosen Firekka as the site for their annual ceremony to praise the Lord Sivar, their highest deity. You stage an assault (together with Firekkan warriors) against the priestesses of Sivar on Firekka, disrupting the ceremony which is a devastating blow to Kilrathi morale. In the end, the Kilrathi leave the planet, driven off by the Firekkan.
I hope I didn't forget anything and nobody replied while I was writing this.
And since I love the WC2 intro, I have to be a smartass and correct you on some Kilrathi names:
It is "Khasra" and "Ghorah Khar", you might correct that in your sig.
Edit: That's unfair you changed your signature!
But I think, your new sig is a bit long.