Far beneath the sea, in a chasm known as "The Deep" a group of scientists and explorers uncovered a new form of life. This microscopic life form was drawn to the explorers' equipment and appeared to have some kind of link to technology. Hoping to use the the life-form to enhance their own weaponry, the scientists quickly setup a small base on the most stable area near The Deep.
In time this small base grew as more and more researchers arrived to study the new life-form. A tower was built near the edge of The Deep which was used for advanced research. Soon after, scientists began extracting small amounts of the life-form and bringing it back to the tower. Very soon they realized their mistake as the life-forms they brought back began to grow and spread within the tower where it was being studied.
The scientists fled the tower because they feared that they might be infected. They called the new life-form 'Viroid' because it appeared to be a virus that could actually infect technology. Fearing that the Viroid would spread, the scientists called in the strongest soldiers from the surface to enter the tower and fight the infection back. You are one of those soldiers.