The story is a mix of shi-Fi and adventure, talks about an high-school boy (he don't remember his name) of 16 years old, that gets kidnapped by an alien criminal organization, the !DTA, with his girlfriend Lucy and two his friends, Yuki and Fushiko;
the !DTA was looking for young age mercenaries, they fly through the stars, razing planets and civilities, just to take the resources to keep this organization alive, when they kidnapped our four main charachters they deleted their memory, to avoid that they could rebel, luckily they engraved on the skin, near the hands, their names, everyone except the main charachter, that will invent the name "Senso" (that means War, pronounced as "Sensou"), he will again make friendship with Yuki and Fushiko, but not with Lucy...
The actual capitain of !DTA is Desert, he's so good, and, at first, the only capitain of !DTA that don't destry planets but HELPS to resolve conflicts, he will takes a liking to Senso, so much to teach his techniques and take him everywhere, he's usually cold-hearted with all his troops, except Senso; after 3 month, Desert and Senso, during a presentation in lab, will accidentally contract a Virus, made to increase the physical abilities and reflexes to the cost of madness, Senso will never know it...
Meanwhile they will increase of grade until they reach the "Level 5", the level of "maturity", where the capitain of !DTA teach you all the principles on which is based the !DTA, Desert, that was becoming increasingly evil because of the Virus, will tell him the true principies of DTA: Destroy Them All, he will start to refuse to fight and to hate Desert, until he meet an alien little-girl, Eiko, that hidden in the spacecraft, Fushiko and Yuki decided to keep her into the spaceship while her planet was exploding, Senso started to talk with her and understood that he should stop Desert once and for all...

The game should be based on:
- Following Desert
- Avoid that he destroy the planet where he going
- Try to kill him

They will do that many times using different strategies, they will save the planets but never kill Desert, because he's too much strong or because he will run away, they will "explore" many planets, orbiting different kinds of stars, with different buildings, landscapes, skyes, technological level and even color of plants (depending of the star)...
After a few planets they will meet again Lucy that escaped from !DTA one month ago, Lucy will again fall in love with Senso but he will be too busy thinking about his mission, until she finally open his heart...
In the last planet (the Earth) there will be the last fight between Senso and Desert...