Walden wakes up on Christmas and gives Zoey a key to his house. Zoey says that giving her a key to his house is premature. He asks if he can meet her parents (who are flying in), but she tells him that next year might be a good time as they are still learning about each other, However, Walden counters by telling Zoey her eye color, pants size and that she runs the faucet to cover her peeing. Walden's mother is coming to visit him. Alan tries to get Evelyn to come over seeing as though this is the family's first Christmas without Charlie. She declines as she is having a "two man sandwich", which Alan learns over the phone in disgust. Walden then wonders where Lyndsey is, but Alan tells him that she has a new boyfriend now, leaving him single and lonely again. Jake calls and tells Alan that he is with Judith, Herb and his sister, actually not being there and is instead smoking pot with Eldridge somewhere else.
Walden's mother arrives and Alan is smitten with how young and beautiful she is. They have dinner, Walden's mother asks if Walden was now a homosexual and hiding it; they quickly due a recap of Season 9 to clear things up. She then explains that she is a primatologist and mainly works with gorillas. Walden mentions "Magilla", an imaginary gorilla friend that he had when he was a child. However, she tells him Magilla does exist and he shared the first four years of his life with him, which lead to Walden learning sign language; she wanted to see if a gorilla baby could learn as fast as a human baby. She sent him back to the jungle after he tried to kill a Jehovah's Witness. This revelation shocks Walden deeply as all his memories of Magilla clear up and he explains that he was so perfect during his childhood because he feared that he would be sent to Zimbabwe just like his gorilla "brother". He leaves in a huff.
At Zoey's apartment building, she opens the door to find Walden holding a bottle of liquor, inquiring if he was drunk; Walden himself is unsure, but thinks he is due to drinking and invites himself in. With hid thoughts muddled with alcohol and anger, Walden questions Zoey's parents, who are very British and appear to like him despite his odd behavior, if they would do something similar to what happened to him.
At the beach house, they then get a call from Zoey, who tells them to come over as Walden is acting crazy. They arrive to see Walden has climbed up to the roof of the complex, where Zoey meets Walden;'s mother and briefly forgets the situation. Alan climbs up to talk some sense into him, telling him how he knows the pain of losing a brother (referring to Charlie's death). On the street, Jake and Eldrige, both baked, eat doughnuts and blankly comment on the situation before deciding to get more food.
Later, Walden is taken to the place Magilla is being kept and reunites with his "brother" after identifying himself through sign language. Alan becomes shocked that Walden's mother brought a taser to stun Magilla if he attacked Walden.
References: A portion of the episode of Two and a Half Men is a reference to an episode of co-creator Chuck Lorre's sister show The Big Bang Theory (The Maternal Capacitance) where Leonard Hofstader's mother visits and Sheldon Cooper has a relationship with her. Unlike Sheldon, Alan fails at having a relationship.
Goofs:Alan says himself to be 44 but Alan is born in 1969 which would make him 42.
Title Quotation From: Walden, accusing his mother for making him live with the constant fear of being sent to Zimbabwe.
This is the last episode in Season 9, in which the late Charlie Harper has been mentioned until Why We Gave Up Women.