A natal chart is a map of the planet's positions in the sky at the moment of birth. In the chart there are twelve houses. Astrology correlates the twelve areas of human experience in the natal chart with the energy of each of the twelve signs.
From approximately the 22nd of February to the 22nd of March, the Sun will be in the sign of Pisces. Each of the twelve signs correspond to the twelve houses of experience in a natal chart (or horoscope). To understand the sign is to understand the function of the "house".
In ancient times the twelfth house was called "The House of Locked Rooms". It governs the subconscious and also what Jung would call the Collective Unconscious. It is where all human experience becomes one -- a world of dreams and demons. Planets residing in this house are imbued with mystery, fantasy, imagination, psychic ability and deep emotion. The twelfth house also represents things and people who are locked away -- orphans, prisoners, madmen, secrets, alcoholism and depression. It's also where redemption can be found.
The last and most numinous of all the signs, Pisces, is ruled by the dreamy and gentle planet Neptune. The symbol of Pisces is two fish swimming in opposite directions that are yet bound together. For Pisces -- a Water sign -- cannot always understand where he is going with his rational mind. He operates from instinct, which serves him well. Pisceans are heir to knowledge that is inaccessible by reason. The end game for Pisces is to find a way to connect to that power.