It's not often you find a series where the second book meets the impact of the first one, but 'Palace of Treason' is definitely it.

The book picks after months of no communication between Dominika and the US, and the novelty it introduces in comparison to the first book are additional spies and a bigger picture of how both Russia and the US leverages their moles. The first book was mainly focused on Dominika, MARBLE and Stephanie Bouchet, but in this one you can see a much bigger picture of the politics between the two countries, as well as international relationships between them and say Germany, Greece or Iran.

Another element that I found very interesting and potentially controversial was the depiction of Putin, and his interactions with Dominika. In 'Red Sparrow', he is a multidimensional character and we get more insight into his way of thinking and plotting. Moreover, Zyuganov becomes much more central to the narrative, and the relationships between different ranks are explained more intricately.