1000 years have passed since earth has become uninhabitable engulfed by a black cloud, covering it in its entirety. Evidence points to sequential massive volcano eruptions or a nuclear war, the fact remains the last human survivors’ dwell amongst 4 massive floating cities, named Cassandra, Bethany, Trishna, and Electra, together amongst other names they are known as “the sisters”, “the four human mothers”, “daughters of Gaia”. The story is centred on a Psychologist, Professor Emerson, who through his patients uncovers mysteries of history’s past and clues of an impending doom which could bring the rest of humanity to meet their grave as it did their ancestors.