After spinning his wheels in series opener The Lost Hero (2010), Riordan regains his traction with book two of The Heroes of Olympus.
Gaea is raising an army of giants to defeat the gods, and Juno has switched heroes Percy Jackson (son of Poseidon) and Jason Grace (son of Jupiter) in order to unite Greek and Roman gods and demigods in battle against her. His memory wiped, Percy knows only that he has another life and a girlfriend, Annabeth; he needs to focus now on winning the trust of the Roman demigods. As per usual, he has two appealing companions with intriguing back stories, Hazel Levesque (daughter of Pluto) and Frank Zhang (son of…?). The three undertake a quest to Alaska to defeat the giant Alcyoneus and free Thanatos, "the border patrol" of the Underworld, assisted and opposed along the way by a pleasing variety of magical beings. Riordan achieves freshness within his formula by giving characters and readers a new environment—Camp Jupiter, similar only in broad concept to Camp Half-Blood—to discover, and his pell-mell pacing has returned. As with all of Riordan's mythological tales, the details that bring the legends into the 21st century delight: The camp's augur reads the entrails of Beanie Babies; tiny, malignant grain spirits dissolve into Chex Mix; the Amazons' headquarters are in Seattle at, well, you guessed it.Should pacing and wit continue unabated into the third volume, whose foretold European setting promises further freshness, fans will eagerly await numbers four and five. (Fantasy. 10-14)