"After annihilating all of humanity except for those in three refugee communities, the virus approaches the remaining humans with a choice that will ultimately decide their fate"--OCLC.
Eighteen months after the plague struck, Leon and Freya hope two hard winters killed it off, but when they set out for a rescue ship they find the virus has been busy.
An unidentified virus wipes out most of the Earth's population and Leon, his mother, and younger sister Grace, who just moved to London from New York, must run for their lives.