Six people are sent to Mars, in the wake of two failed missions. On landing, they learn that their return vehicle has also failed, and they are stranded. Their only hope is to trek across thousands of kilometers to a return vehicle unused by one of the previous missions—and that ship can only hold two people.

The story is told in shifting episodes, from person to person, weaving their individual memories in with their shared present. A mixture of adventure, survival, and whodunit, it’s well paced and gripping. And in the end, if not everyone can return, what do you do? The question stayed with me long after I’d put the book down.