The Battle of the Labyrinth camp for the school year. On his fifteenth birthday at the summer's end, Percy receives a visit from his father Poseidon, who gives him a sand dollar, admonishing him to “spend it wisely”. Nico later appears to tell Percy his plan to defeat Luke once and for all. "The Battle of the Labyrinth" was initially referred to as "Percy 4" until the title was officially revealed. The novel was teased by Rick Riordan behind the pages of its predecessor, "The Titan's Curse". It was based on the Greek myth of the labyrinth, where the Minotaur was supposedly kept. In his
The Battle of the Labyrinth fifth and final showdown between gods and monsters next year." Matt Berman of "Common Sense Media" was one of few reviewers to mention the differences between this book and preceding ones in the series. He highlights "The Battle of the Labyrinth"s darker tone, more mature themes, and increased discussion of what it philosophically means for the characters to follow and support the Greek gods and Titans. He concludes, "Up until now the series has been great fun, but little more. Now as it begins to grow, like the Labyrinth, larger and deeper and more complex, it's even more fun." Despite