Okay kiddo, so the Nazis were a group of people who ruled Germany a long time ago. They believed in a type of mysticism that was called Nazi mysticism.
To understand what Nazi mysticism is, we need to understand mysticism first. Mysticism is when you believe in things that are not real or cannot be seen or touched, like ghosts or magic.
Nazis had some beliefs that are considered weird or strange. They believed in things like ancient Germanic folklore and the idea of an "Aryan race." They thought that people with blonde hair and blue eyes were superior to others, and they were the perfect and purest race.
Some people also believed that the Nazi's leader, Adolf Hitler, had magical powers, and he was going to lead them to victory in the war.
They did some crazy stuff like trying to search for holy relics like the Ark of the Covenant and the Holy Grail, which they thought would give them magical powers.
So, in conclusion, think of Nazi mysticism as a bunch of weird, made-up ideas that Nazis believed to justify their crazy behavior.