Ish, a solitary young geologist, barely survives a snake bite; after he wakes from a coma, he drives to the nearest town only to find dead bodies; he searches for survivors, from San Francisco to Las Vegas.

Ish finds a survivor and feels a romantic spark; he feels the need to see if it real, or if it is the reality that they are last two people on earth; rats plague San Lupo; Ish dreams of rebuilding civilization.

New survivors appear but Ish doesn't trust them, Emma invites them in; a bad storm slams San Lupo.

A drought hits San Lupo; a nomadic group arrives that knows how to find water and want to trade; Ish has his doubts, but chooses to accept help.

Ish catches Charlie assaulting Evie so San Lupo must decide how to punish evil; the virus returns and Joey falls ill; Ish feels humanity's future hanging in the balance.

San Lupo fights for survival against the virus; Ish realizes the answers to humanity's future may not be in his books and finds Joey's secret project.