After the human race has been wiped out, Del lives in an empty town, content in his solitude and the utopia he has methodically created for himself, until he meets young Grace, who wants to stay with him.
Michelle and Allen, who have reached the point in their relationship where they are considering next steps, decide to invite their parents to finally meet and to offer some understanding of why marriage works. Except the parents already know each other quite well, which leads to some very distinct opinions about the value of marriage.