The Protector of Memories is Part II in The Veil of Death Series; a story of the paranormal and ghostly kind with a subtle hint of alien species known as 'the immortals'.
When Hera is banished into The Void of Emptiness as an empty ghost, her life-force unlocks all those within it from their state of emptiness, but it does not free them from the sticky, black substance that keeps them imprisoned. For the second stage of her plan to work, Hera requires a lot more stardust than the meagre portion, Zeus threw in after her.