Complex sentence: Inside the statues of the Hokages, Gennou is explaining it all to Naruto: the true target of his explosions is the mountain itself: the right sort of blast will bring it down right on top the village, destroying it.
Split into simpler sentences: Inside the statues of the Hokages, Gennou is explaining his plan to Naruto: the true target of his explosions is the mountain itself. The right sort of blast will bring it down right on top the village, destroying it.