I found this fast-paced and hard to put down. The plot A of overcoming grief combined with the plot B of a mystery hole on a planet worked well together, both literally and metaphorically. (if a little obvious) I didn't find the end quite satisfied, because while the plot A is resolved, the plot B left a lot of questions unanswered. As such, it felt less like a novel and more like a long short story in structure. The character dynamics were the most page-turning part of the book, imo. I also liked the small details and tech strewn throughout that gave everything veracity and depth.