In this mecha anime (mecha is short for mechanical, this term refers to anime where the usage of robots or mechanical devices are a main theme), in the near future, or Cosmic Era, genetic manipulation has advanced to such a stage that the populance has been divided into two: 'pure humans' and genetically modified humans, called 'Coordinators'. Mutters against genetic modification and the envy of pure humans towards the more agile, more talented Coordinators have caused strained relations between the two groups, finally erupts into war when the humans begin killing the 'non-human' Coordinators. The war finally came to a head when the human military, the Earth Forces send a nuclear onslaught to the space colonies of the Zodiac Alliance for Peace Treaty, ZAFT (the military protecting the Coordinators), causing complete destruction of a heavily populated space colony. This tragedy is given the name Bloody Valentine, and the war that followed, the Bloody Valentine War. The highly technologically advanced ZAFT (perhaps due to their genetic advantage) retaliated by sending MS (mobile suits, a machine-cum-body armour piloted by the Coordinators) with Nuclear Jammers to the Earth, thus negating the Earth Forces' significant nuclear arsenal. The war then went into full throttle, with battles taking place on land, sea and outer space.
Now that was complex, right? You bet! If you are a machine-lover, you will go mad over the many types of MS and battleships represented in this anime. Sometimes I wonder where the mangaka gets his ideas... Battle strategies and tactics are also used unreservedly here, for those interested in military strategy. And the various emotions and actions of the highly complex characters fleshed out in this anime will appeal to those more in touch with their emotions. It is an anime that has something for almost everybody. Notice the almost? DO NOT watch this if you do not like war nor the sight of someone of killing someone. That theme is prevalent in this anime. And to those who have preconcieved ideas (like me during the first few episodes), the matter of who is right and who is wrong is not in black and white, but is a very greyish shade of grey in this anime. All in all, good artwork (especially those GUNDAMs, very well drawn) and storyline, if you do not mind the complexities. The characters are well fleshed out and are seldom not what they are... If war and machines are your cup of tea, this is the anime for you.
P.S. - GUNDAM is the name given by Kira to all MS developed during and after Strike's development. It is actually an acronym for what appears on the main screen in the pilot's cabin when the MS is started up. If I am not wrong, it stands for General Unilateral Neural Defensive Autonomic Manuever.... Hahahaha.... SEED refers to a state of mind for some humans (though more prevalent in Coordinators) where they lose control over their emotions, making them brutal and efficent killing machines, also known as a beserker rage. Familiar to some gamers out there, I am sure...