Hi,
I study astrology through an alternate house system, yet whichever is used I believe natal Pluto would remain in the same 12th house.
The 12th house has a number of interpretative reputations, including that of being the realm of one's life that, for one reason or another, inclines to remain hidden from not only public and external view but also within and from one's self.
Pluto in its own sign, Scorpio, runs deep. It can be led by its controlling compulsions and obsessiveness. Everything is based upon how it interprets life through the inner emotions aroused when dealing with it.
Whenever it aspects positions in a chart, which may not be too often because of its slow daily motion, it can 'upset and overturn the apple cart' of one's daily existence to bring about a new and unexplored manner of expressing it.
In the chart shown, neither Sun or Moon are natally aspected to natal Pluto. It could mean that in those periods it adversely aspects either, a sort of 'bulldozer effect' occurs that totally destroys and eradicates what was to allow the new perception (or 12th house introspection) of life to replace it.
Sun and Moon form a (out of sign) natal square (inter-parental issues that can influence one's take on life?). Such an aspect can infer conflict between 'how I feel' (Moon) and 'What I want'( Sun); a FIRE aspect between them says much about an inflammatory ' me first in importance and attention' that may not always occur as one would wish. The 'everyone/everything is against me', or 'I can't do anything about it', inner explosion of temper (opp. Mars) through the 'hidden enemies' could become a controlling/out of control factor; especially covering those realms of life with which it forms the T-square with planets across the Leo/Aquarius axis. Yet the true enemy is within one's own approach to those situations.
The outer planets energies are significant of ' the necessity for conscious awareness' to occur. The forthcoming square aspect of Pluto to Moon (feelings) and then Sun (will) can hopefully bring about a bulldozer effect in the most positive sense.
Pluto always seems to answer 'WHY?' circumstances occur as they do/did because we are/were as we are/were. Hopefully when the transiting aspects are complete, you will have found it within yourself.