And we are off and with Percy again.
This is structured like The Lost Hero, third-person with three rotating viewpoints, except of course this time one of them is -- surprise! -- Percy, so we know him. There are some spoilers for The Lost Hero, and more for the original series.
Percy is all but completely amnesiac prior to being trained by a wolf named Lupa -- which is before the action, and only remembered. (Perhaps it would have been better to at least show her -- it seems a little too media in the res.)
But it starts with him, running away from gorgons, who won't stay dead, and some instinct is directing him to a place -- a tunnel under a hill, where a side tunnel guarded by a girl and boy. On the other side of the highway, of course. An old lady asks him to carry her across the highway, and he does so. Fortunately the kids on the other side help against the gorgons, and he manages to reach Camp Jupiter. She manifests as Juno and gives orders. And he gets to look at the camp. Which is filled with not only demigods but ghosts, one of whom recognizes him as a Greek.
Hazel, the girl, who has quite some secrets of her own, takes him to Octavian, who eviscerates stuffed animals to read their entrails and declares Percy is fit to join one of the cohorts. There is considerable intrigue in the camp. He gets inducted into the Fifth Cohort, which is Hazel's and the boy -- Frank's. After he distinguishes himself in their war games, Mars appears to claim Frank as his son and send him off on a quest. It appears that Thanatos was taken captive (a la Sisyphus's stunt) and that's why the monsters aren't staying dead for any time. Plus Percy has to go with him.
He takes Hazel, too, and they are off to save death. And find out about an invasion. And learn secrets of Frank's heritage and Hazel's past. And met a red-winged harpy. And Percy, to have dreams about his old friends.
Fun story. I'm looking forward to the next, because while this does have a complete story, the threads leading on to the next are heavier in this book than in the last.