The year is 2022, and after an unlikely event, only one man is left on earth: Phil Miller, who used to be just an average guy who loved his family and hated his job at the bank. Now, in his RV, Phil searches the country for other survivors. He has traveled to every city, every town and every outpost in the United States, Mexico and Canada, and has found no one, which leads him to the painful realization that he is almost certainly the last living being on the face of the earth.
Pamela finds her place within the group as they all set sail for Mexico, avoiding the apocalyptic nuclear fallout in the United States. Their course derails a bit when they realize that none of them knows how to actually navigate a yacht.
Tandy devises an escape plan to get away from Pamela and back to Carol and the others. Meanwhile, the rest of the gang encounters a castaway, Glenn, who has been stranded on an island for years.
Pamela tries desperately to redeem herself with everyone, as the gang finally reaches Mexico. Meanwhile, Todd is disappointed that Zihuatanejo is not the paradise of which he'd dreamed.
Carol panics when Todd and Melissa leave for their honeymoon and Erica and Gail decide to live on their own for a while. She and Tandy devise the ultimate plan to convince everyone it's safer to stick together.
The gang settles into an old mansion previously owned by an infamous cartel leader. While Carol forces Tandy to put down his new toys so they can baby-proof the giant estate, Melissa worries about Todd's physical health and Gail and Erica can't figure out why Dawn won't stop crying.
Carol's pregnancy takes an unexpected turn, and while Tandy feels ready to face the challenge head on, Gail is concerned and wants to intervene. Meanwhile, Melissa discourages Todd's baby fever.
Tandy goes to great lengths to convince everyone he's a feminist. Meanwhile, Carol gets jealous of the time that Gail spends with Erica and Dawn, and Todd tries to be a father figure to Jasper.
Todd asks Tandy for parenting advice when he notices that Jasper is acting more reckless than usual. Meanwhile, Carol and Erica realize that Jasper may be the only potential suitor for their babies and begin vying for his attention.
Tandy and Todd stumble upon a new survivor, Karl, who has been trapped in a high-security prison in Mexico ever since the virus hit.
Tandy and Todd introduce newcomer Karl to the rest of the gang. Meanwhile, the group searches for Jasper, who has gone missing.
After the graveyard incident, Tandy and Todd try to convince the rest of the gang that something is majorly wrong with Karl and something needs to be done. Meanwhile, Jasper is still missing.
Tandy tries being a helpful, responsible adult in order to finally win Gail's praise. Meanwhile, Todd is furious with Melissa for keeping him away from Jasper.
Todd sinks into a deep depression, leaving the rest of the gang to console him. Meanwhile, Tandy and Carol can't keep their hands off each other.
While Todd butts heads with Erica, Melissa is determined to form a strong female friendship with her. Meanwhile, Carol grows suspicious that a new stranger could be living nearby.
Tandy wakes up to a shocking discovery that is positive for everyone in the group, but it throws Todd into a spiral. Meanwhile, Todd and Erica share an emotional roller coaster.
A thermal heat detector reveals a potential sign of life outside of the Zihuatanejo village, but Tandy doesn't want the group to split up to go investigate. Meanwhile, Todd and Erica have trouble seeing eye-to-eye.
The gang ventures out in search of what they think could be a new sign of life, but are surprised at what they actually find. Meanwhile, Todd makes a few morbid discoveries of his own back at the mansion.
After discovering hidden dangers in their mansion, the group decides to part ways with their home in Zihuatanejo and embark on a new destination. However, Tandy has second thoughts about what they may be leaving behind.