Plato is an interesting man, with stupendous caliber to contemplate and make philosophies of the human nature and the universe. His contemplation of the human soul was quite fascinating. It almost is a compelling idea to believe (an absolute truth).
The soul, according to Plato, is immortal. Like Socrates, Plato believed in the world of opposites; that if there is life, there is death; that if there is beauty, there is ugliness. Similarly, Plato in "Phaedo" has Socrates explain the immortality of the soul. He explained that "life generates death, and death proceeds to another life;" the soul hence exists before it enters the body and continues to exist after the body dies. Plato further on goes on to say that the soul is like a body that constantly keeps changing its clothes; this concept is totally relative, though nonetheless, I believe in the immortality of the soul, and that the soul is the realm of reason. Unlike a soap bubble that exists for only a few seconds, and unlike everything that is palpable in this world, the soul is eternal and immutable. It is fascinating when Plato says that the soul can survey the "world of forms, or ideas" - the significant other to the "world of the senses". "Forms" are eternally good, true and beautiful.
In Plato's dialogue "The Republic", the soul was explained in three parts: the reason (rational), the spirited (nonrational/will), and the appetites (irrational). The rational part of the soul has divine intelligence and because it can contemplate on the "forms", the body and the whole sensory world is experienced as imperfect and insignificant. Assuming that the three parts of the soul is well understood, it would be important to also note that "the will is neutral and inclined to follow reason, but it can be pulled in either direction" - that of the "appetites too.
In our day-to-day lives, the realms of the soul are always active, if not actively, then vigorously.