The One Standing at the Door

Metro 2033: The One Standing at the Door is the debut novel by Olga Shvetsova, written as part of the Metro 2033 universe. The thirty-eighth book in the series, this novel serves as the first entry of Olga's Heroes of Our Time trilogy.

Synopsis
What could be more important to the survivors of the nuclear madness that has destroyed the world than a bunker? Shelter. A home. A fortress. And what could be more important to a bunker than a door? A massive hermetic seal with a heavy "hand wheel". It is the boundary between the safe "here" and the deadly "there", the terminator between the two worlds. But is it always the enemy outside, and always the friend inside? Who are you, standing at the door?

Interesting facts

 * The title is suggested by the editor.
 * The technique of having multiple characters in different episodes is one of the key features of George R.R. Martin's epic novel A Song of Ice and Fire. That said, Olga read his books after writing her debut novel and was surprised by some of the plot similarities.
 * Olga called the image of Denis on the cover "a cuckoo in the hood".