The episode 'Success' features three main plotlines: a man giving in during an apocalyptic evacuation; a day shadowing an action star that turns disastrous; and a country singer's music session that becomes nightmarish.

Key characters include Rex Henley, the country music star played by Tom Segura, who is involved in the nightmarish music session; an action star whose day turns disastrous; and a man involved in the apocalyptic evacuation scenario. Robert Iler also stars, likely connected to one of these storylines.

The country singer's music session becomes nightmarish, implying that the session takes a dark or disturbing turn, consistent with the show's dark comedy tone. Rex Henley, played by Tom Segura, is the country singer involved in this plotline.

In the episode, a man gives in during an apocalyptic evacuation, suggesting a moment of surrender or breakdown amid chaos. Specific details of his actions or consequences are not provided in the available summaries.

The day spent shadowing an action star turns disastrous, indicating unexpected problems or mishaps. The action star character is not named in the summaries, but this plotline is one of the three main stories in the episode.