The North and South Nodes are the points where the Moon’s Orbit crosses the Earth’s orbit around the Sun. So they’re not planets. They are exactly 180º apart in the sky and are always retrograde. As they are always in ‘opposition’ they are considered as axes, when the North Node is in the First House the South Node is in the Seventh. Similarly, when the North Node is in Aries, the South Node is in Libra.
The North Node indicates the challenges that we are to face during our life on Earth. It indicates the lessons to learn in this life. The ruling planet of the sign occupied by the North Node is an indicator of the ideal way to face the challenges or lessons during this life.
The South Node indicates what we are comfortable with, the lessons previously learnt and brought into this incarnation to help overcome the challenges we are to face in this life. The ruling planet of the sign occupied by the South Node is an indicator of what we did to learn these lessons.
The sign and house placement of the North Node represents circumstances and activities that usually feel unfamiliar. The sign and house placement of the South Node tells where you have a tendency to totally overdo things.