The story
The name is short for Urabon, the Japanese reading of the same Ullambana sūtra that gives China its Ghost Festival — Mokuren finding his mother among the hungry ghosts and being told to feed the assembly of monks to free her.
He danced when she was released, and that dance is the Bon Odori, which is now a circle dance round a tower in every neighbourhood, to a song particular to the region.
The dead are held to come home for the three days and then go back. Almost everything done is about the route: showing them in, feeding them while they are there, seeing them out.