After the previous book I'd expect we would at least keep the more urgent pace, considering the imminent attack on the Roman Camp and what not. But it doesn't.
The first half of the book is a drag. It feels like a repetition of the exact same formula we've seen in the other three so far, but here it makes even less sense because the little silly social misteps are not even close to something to be worrying about, and yet! There's also a new character, Lavinia, with whom we waste a considerable amount of page time for no reason. She doesn't improve Apollo's journey whatsoever, nor teaches him any lesson. She's just there.
The second half is considerably more interesting, but I have to take note on how much grimmer this instalment is. Even Apollo's self deprecating jokes lean way more towards self deprecating than to jokes. Is important that we are finally seeing consequences, and I enjoy a darker tone, but this might've been a bit of a killjoy.
Overall, this book seems a lot like a filler. The few important plot points could've easily been integrated in other parts and the series made into a faster-paced trilogy.