There's an area (or country) called Timber where Rinoa lives. Timber was taken over and occupied by Garbadia. Rinoa is a leader in the resistance movement called Owl of Forest. She and Seifer are acquaintances.

After seizing a TV tower in Principality Doll, the president of Garbadia, Deling, declared war on the whole world. A witch, Idea, is behind the Garbadia plots. So, Rinoa goes to Balamb Garden to ask them to assassinate the witch. Then SeeD (including Squall and Zell) and Rinoa and some people from Garbadia Garden will hit the road to kill the witch.

In the demo, the Dollet Dukedom (Final Fantasy 8's world is made up of 'Dukedoms', the only other known is 'Balamb Dukedom') is at war with the Galbadia Army and have requested help from the elite SeeD force (that Squall is in). Here is the demo's prologue:

"The Dollet dukedom, at war with the Galbadia Army have requested 'Garden' to dispatch 'SeeD'.

The world renowned special team 'SeeD' from 'Garden'

The high-speed vessels in which they ride are about to land in Dollet dukedom..."

Garden is a military school where six to nineteen year old boys and girls gathers to learn military skills. Each country in the world decided that graduates of the Garden would form a private group. Not depend on any of goverment departement or army Assignment to any army was compulsory for Garden graduates depending on whether negotiations were made between the Garden's staff and a certain country's army. Graduates could become commanders of a foreign army, but couldn't pick their place of duty. However graduates from the garden to it's not the main archive of the students their main archieve was to join SeeD.

SeeD was an elite force or special force group dispatched by the Garden. Each member of SeeD has high ability , but widely differs in battle capabilities. Garden cadets may opt to take the SeeD Entrance Exam instead of taking Final Exams, but passing the test is extremely difficult. The duty of a SeeD member ranges from guarding to riot suppression, regardless of every possible battle condition. Squall Leonhart apparently has a past with SeeD. It's not known whether he was part of SeeD from the beginning of the game, or developed some sort of relationship along the way. What is known is that he was once part of Garden.

Then the legendary witch Edea has awoke from the long silence Edea has an image of a witch in the occidental culture. She is an enemy for Squall and his fellows. But what does her existence in the world, where Squall and his friends live, mean? Fundementally witches have been the only women that have powerful magics. Though they have existed since ancient time, the reason why they exist is unknown.

They are not immortal but have the fatal thread like humans. A witch can pass her power as a witch on to the person she chooses. It is said that witch's power does not run in the blood, so a person chosen by a witch suddenly gets a tremendous magical power, and sometimes such a person's life would be changed dramatically.