Pluto
Pluto governs transformation, power and what cannot be undone. It was discovered in 1930 and reclassified as a dwarf planet in 2006.
Governs
Pluto describes the area of deep, irreversible change: crises after which a person becomes someone else. It is associated with power, control and the repressed, and also with collective processes: the masses, money on a large scale, the underground.
Its cycle is 248 years, with 12 to 32 years in each sign because of its highly elongated orbit.
In the signs and houses
Pluto's sign describes a generation and its main collective theme.
Its house shows where irreversible changes happen in a person's life: in the eighth, through crises and other people's resources; in the fourth, through family; in the tenth, through power and reputation.
Strong and weak placements
Ruler of Scorpio in the modern tradition; in the classical tradition, the ruler was Mars.
Since 2006 Pluto no longer counts as a planet astronomically, but astrologers keep using it. That is telling: what matters to astrology is not an object's astronomical status but the established tradition of interpretation, which in itself says a lot about the nature of the method.