I am currently listening to Multitude by Dean M Cole, narrated by RC Bray. It is the sequel to Solitude. In the first book a mysterious light wave makes all animal life on Earth, including humans, disappear. The only survivors are Vaughan Singleton, a test pilot, and Angela Brown, an astronaut who is surviving with dwindling resources on the Space Station. Vaughan must find a way to bring her back to Earth.
In the second book Vaughan and Angela are trying to discover what the light wave was.