It's Christmas time at the Harper household, and Alan is preparing a feast for Christmas Eve for the family. Evelyn shows up an ancient television producer, Marty Pepper (Carl Reiner), who she's trying to get the estate sale on his 60 million dollar property when he passes. Charlie gives Berta her holiday gift, and she chooses to hang around for the holiday as a guest.
Everything seems like it's going to go well at the Harper Christmas dinner for once, until Jake is checking out some cute girls by the beach. Charlie sees him and encourages him not to be in a committed relationship with Celese at only 13, err 15. With Celese out of town, Charlie convinces him to go talk to the girl and he does and eventually invites her back to the place. When Jake goes over to the girl's aunt's home, Celeste comes over to give him his present. Jake returns home with the girl in front of Celeste, and suddenly he has no women. Chelsea comes home and overhears the advice that Charlie gave Jake and is pissed for obvious reasons. Now we have the awkward Harper dinner we're used to.
The episode title, "Warning, It's Dirty" was said by Marty as he warned before telling a story.