Rainbow Factory, an important experimentation factory, is hidden from society due to the type of experiments that are carried out within the facilities. The head of research and experimentation is Walden Darling, a renowned scientist for his discoveries in experimentation, developing cures for diseases such as biological weapons.

Due to his strong temperament, coupled with the recent death of his adopted daughter and the divorce from his wife Julie, he has been in a very bad mood that he does not even try to separate these attitudes from his work from his personal life.