Here Are the 3 elements that this story has:

Monsters - Ferocious, fast moving?, zombies have come to inhabit the world....

Enclosed Forest - Our hero, carrying the Replicator device, has to walk through a forest infested with zombies and paranoid survivors.

Sin of mankind - Mankind pays for its ignorance, by facing extinction.

Will the Replicator reach the scientists refuge before its too late??

Comments and suggestions welcome!
1,2,3 Go!