Ok, blargh, another post to this friend for background info if he wants it.
In the UC all the stories basicly follow the same sort of plot with some deviation, a few of them taking place in the same time as the first series.
for Gundam Wing five Gundams are sent to earth from the colonies to be used for terrorist activities agaisnt the earth sphere's military who are very oppressive.
G Gundam is wierd, its like dragonball with robots. All the space colonies (based off of nations (neo japan, neo america, neo germany) send Gundams to fight in a giant tournament on earth.
Gundam X is diffrent from the others, it follows a what if based on the original series if a dozen colonies had been droped on earth instead of one. Its has a very post apocalyptic storyline
Gundam Seed basically is the original gundam series and Zeta gundam mixed into one homogenized series, plots characters and such are all recycled.
Turn A Gundam is an odd one. Humanity, on earth, is developed to about the point of the 20th century, maybe earlier, the 19th or so, still using Bi-planes. earthlings that in the past been relocated to the moon and not allowed to return invade earth. The story is based around a moonrace scout that joined the earth militia using the Turn A gundam to fight.
Turn A is the oddest of the series for two reasons. First the mecha design is completely different from any of the previous series.
compared to
The biggest thing in Turn A is the revelation that all of the diffrent series and timelines are part of the same timeline, with the Universal Century being 3000 years before Turn A. You can see two of the 'good guys' using unearth Zaku I and Zaku II suits