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.

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.

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.

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

Ish finds a survivor, EMMA. There's a spark. Is it real, or are they just the last two people on earth? Nature is unrelenting. RATS plague San Lupo. Ish dreams of rebuilding civilization, but can they even survive extinction?

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.