The monsters are always determined to kill the demigods. Percy and his friends Annabeth, Grover and Thalia find themselves facing a horrible manticore. Their lives are only saved thanks to the intervention of the goddess Artemis and her Huntresses. But, when Annabeth and then Artemis disappear, a new quest strewn with pitfalls awaits: Percy will have to be more wary than ever of the manipulations and traps of Cronus, the Lord of the Titans.