This book reminded me a lot of the Tarkin book. Thrawn and Vader go on an adventure. It’s very interesting to see the way Palpatine is trying to get them working closer together, and the way Thrawn accomplishes the same discovery Tarkin made about Vader’s origins.
This story is an A/B story. We jump back and forth between two adventures. The second one is from some time before, when Thrawn and Anakin went on a very similar journey to the same locations for a different reason.