In the far future, humanity has spread to several planets but not yet encountered any aliens. Our protagonist, Kim, is one of those involved in actively searching for alien life. So was her sister, Emily, until her mysterious disappearance a few years ago. A clue starts Kim looking into her sister’s death, where she finds more than she bargained for.
The worldbuilding is well done and the plot is superb. It has an excellent balance of twists and foreshadowing, so while it is obvious that aliens will make an appearance in the book, the details of how that will happen remain a surprise.
My main objection to this book was the Mary Sueishness of the protagonist, especially in the last third of the book. She singlehandedly outwits the entire government, which has not bothered to have her followed even after the initial clash. McDevitt includes an acknowledgement that Kim has taken it upon herself to make decisions for the entire human race which she has no authority to do, but he doesn’t mention how unlikely it is that she is so successful at this.