While Stan, Kyle, and Kenny discuss their plans for New Year's Eve that leads into the new millennium, Cartman rushes up to explain he's finally gotten his period since he had bled out of his anus. Disbelieving him, the boys ask a female about it, as she explains that they have mistaken Cartman's explanation to be true.
Outside Jesus' house, the media and residents of the town have arrived and are talking about how Jesus will do something for the millennium. Surprised by this, it dawns on Jesus that he has been given the chance of a comeback. He steps outside and is told by the people that they want to see God. Jesus goes inside and visits Heaven where he asks God if he will appear for the millennium, to which he answers no. Taken aback, Jesus comes up with another plan; he will hold a comeback concert for Rod Stewart that will take place in Las Vegas, and everyone's invited.
At his home, Kenny is in the bathroom when he discovers that he too has bled out of his anus and believes he has had his period. A news report, however, reveals that a colon infection has spread across town; the boys do not see it and remain oblivious.
After discovering that Kenny has had his period, Kyle decides to lie that he too has had his upon consulting Ike on the problem. After Kyle's false revelation, Stan his disheartened when the others form a group for "mature people only", in other words, those who have bled out of their anus.
Stan then goes to Chef for advice and tells him that "he knows someone who hasn't had theirs while everyone else has", Chef believes it to be obviously an important female person in his life. Upon hearing he will just have to wait, Stan gets angry and says how bad he wants his period, to Chef's surprise.
Stan next goes to Dr. Mephesto and lies that his father never went through puberty, Mephesto gives him tablets to give to his father. Stan takes the whole bottle and hopes for a period.
Obviously, it does not work yet, although Stan has developed facial hair, breasts, and his voice has broken. Cartman will still not let him in the group though. At their club, the boys discuss various things and even insert tampons up their rectums, which kills Kenny. Jesus has managed to get Rod Stewart to agree to play, despite him being in a nursing home and having little bowel control.
At the event, Rod Stewart "poops his pants" and cannot play. The audience becomes furious and prepares to crucify Jesus once more, who goes to sulk along with Stan. Stan explains his issue, to which Jesus replies that God can't deal with everybody's problems or there would be no point to living, upon saying this, Jesus realizes he shouldn't have relied on God to make himself popular once more but will have to do it himself.
Suddenly, a beam of light appears on stage and God appears to everyone who are surprised at his appearance. Mr. Garrison asks about God, who replies with "What did you expect me to look like?", Garrison replies "Well not like that!". God explains he will answer one question as it is a new millennium. Stan seizes the opportunity to ask why he hasn't gotten his period, to which God answers that Cartman and Kenny have the colon infection and Kyle is simply lying. God then explains he has answered his question and will appear again for the year 4000. Jesus is happy once more but the crowd is not; they then advance on Stan for using up the one question. He is attacked by the audience as the closing credits run and tries after trying to calm everyone down by singing "Auld Lang Syne"(poorly due to his broken voice).