This passage of the tale told by Lindo is a continuation from the previous chapter “The Theft of Melko and the Darkening of Valinor”. It features how a group of the Eldar, notoriously a lot of the Noldoli, leaves Valinor and wanders north in order to access the world, that is, the Great Lands (or Middle-Earth as we know the continent as in Tolkien’s later works).
The first part of the chapter "The Music of the Ainur" consists of a text which picks up from where the "Cottage of Lost Play" ended. It mainly describes a meeting between Eriol and aged Rúmil who dwells at the cottage and cares for the garden. This part forms a link between the "Cottage of Lost Play" and the tale of "The Music of the Ainur".