The first of the social houses, the seventh house is opposed to the first house literally and in emphasis: in the first house we put our energies into the world; in the seventh the world puts energy back into us. The purpose of the seventh house is to bring about greater self-awareness through relating to what we experience as being outside of ourselves. This may in fact be energy within us that we have rejected out of fear or the need to experience it more objectively or externally. This is called projection, and we seek projected parts of ourselves in our intimate relationships.

Thus the seventh house rules intimate one-to-one relationships of all kinds (including marriage, business and counseling relationships), open enemies and conflicts, lawsuits and the lower courts. Planets in the seventh house indicate areas in our lives that need relationships to bring them out, and the houses ruled by seventh house planets are those "areas." Many planets here indicate many needs that we are looking for others to fill. In this case many relationships (or more than one marriage) is probable, as it’s unlikely that one individual would fill all those needs. Individuals with so much projected energy feel a void in their lives, and may encourage others to be dependent, or even pick fights rather than be alone.

Astronomically speaking, the seventh house is that one-twelfth sector of the local sky just above the western horizon (see above picture) occupied by planets in the two hours just before they set.

With the planet of sex and death in your seventh house, your intimate, one-to-one relationships are the arena of your personal growth, transformation, evolution, and aspirations for power. How this manifests in your life depends on how Pluto aspects other planets and the angles in your chart, and on what house Scorpio rules in your horoscope. Planets in the seventh house generally symbolize projected energy, that is, your own energy that you deny yourself conscious use of. In the case of Pluto, this self-denial causes you to seek out powerful, intense individuals to provide you with what you sense is rightfully yours—that which you know you deserve and want to live out. But because you deny these energies to yourself, being up against someone who has what by right (self denied) is yours can make you angry and jealous of the other and what he or she has. Your intimate relationships may therefore serve, in part, as a battleground with many power struggles, sudden changes, and endings. Trines and sextiles to Pluto indicate experiences in which you can learn about the use and abuse of power from your partner(s). With such intensity and potential explosiveness here, it would be helpful to examine your motives when you enter into a relationship. There's a lot of unconscious energy here, and you may need to learn to compromise and to not dominate your partner so much. On the other hand, you may need to become more aware of your partner trying to dominate or to control you; it can work both ways. These things are not intrinsically bad; they are just the particularly intense flavor with which you become intimate. The issue here is to become more aware of who you are, and what unconsciously drives you to do the things you do—the long arcs of your life. Each human being has her or his flavor. It is important to get to know your own.

If Pluto is within 10° of the descendant (seventh house cusp), then it is conjunct the descendant and much of the foregoing is even more strongly emphasized. If Pluto is in the sixth house AND within 4° or 5° of the descendant, then it is said to be on the "dark side" of the seventh house, and its influence will be felt in the seventh as well as in the sixth house. The closer a sixth house Pluto is to the descendant, the more it will be interpreted as though it were in the seventh house; when less than 3° from the descendant, a sixth house Pluto expresses itself primarily—and eventually entirely—in the seventh house.