You should read the Trials of Apollo because of the action.Meg, Apollo, and Reyna are at the silent gods cage.  At the top of a cell tower.  They break their way in and free him.
Apollo you cannot kill me
I might not be able to, but I will die trying
They climbed up the tower even though the crows were trying to attack them.
I will die killing you
Apollo, Meg, Lavinina, and Hazel are in the Tyrants Tomb.  Then they start a fight on accident with the tyrant.
Come down from up there you four
Apollo shoots at Commoduss hopelessly because his skin is impenitrable.  Apollo hopes Franks plan works.
Frank holds caligula against the wall with one hand while lighting his life souce would log with the other.Read the book to figure out if they win this fight and if Apollo succeds on his journey.