The Tyrant’s Tomb (The Trials of Apollo #4) by Rick Riordan

Aprl 8th.

According to the hideous driver's license his father, Zeus, saddled him with when he turned him from an awesome god to pathetic mortal Lester, that's Apollo's new birthday.

It's the same day the emperors Caligula and Commodus plan to attack Camp Jupiter, the training ground for Roman demigods; it's also the blood moon, when an evil king intends to unleash his army of undead.

Joining the fun is the Cumaean Sibyl, who has an ax to grind-on Apollp. It promises to be a bash everyone will want to miss.

Apollo's demigod allies, plus the entire Roman legion, are preparing for battle. Ella the harpy and Tyson, her Cyclops friend, are searching the Sibylline Books for helpful prophetic hints.

The camp's healers are trying to cure a stubborn infection Lester received from ghoul's claw. But even all this aid won't be enough to compensate for his weakness....

It may finally be time for Apollo to call home.

But will anybody on Mount Olympus pick up?