After an intense three-day session in OR, Hawkeye begins writing a letter to his father, Dr. Daniel Webster Pierce, about the goings-on at the 4077th as the 25th of December approaches, a Christmas they were once promised to be home by.
At first, Pierce describes the nightmarish session in OR, which is gotten through by bickering, innuendo and other tension-cutters that Hawkeye feels he must explain to his fellow physician and father. He gives a decidedly mixed compliment to his CO, Lt. Colonel Henry Blake, calling him a nice guy but making him feel a bit like he's on a sinking ocean liner commanded by Daffy Duck.
Since the number one enemy at the camp after Death itself is boredom, a series of rather large packages sent home by Radar pique the curiosity of Hawkeye and Trapper John McIntyre, whose flouroscope inquiry reveals something semi-felonious. Radar has been mailing home a jeep, taken apart and mailed piece by piece, though this seems to be not unique, either for the 4077th or the army, causing Hawkeye to predict a retroactive hernia for Radar's mailman in Iowa when he's told what he delivered.
Pierce describes admiringly and with no envy the Sisyphean task faced by Father Mulcahy, keeping morale and spirits high all while trying "to give this cesspool a yuletide feel" via some makeshift decorations. His unofficial job as camp referee becomes all too real as a recalcitrant Frank Burns finally pushes Klinger too far, causing one of several punch-outs the Major would receive during his time at the 4077th - to cheers and accolades from the patients and staff in OR. As an enraged Klinger returns with a grenade he intends to feed the knocked-out Frank, the Padre intercepts and calms the for-once in-uniform soldier, and manages to persuade the local MP to forget he heard of anything.
While pursuing the amorous company of several nurses, hecklers Hawkeye and Trapper manage to make a complete ruin out of the partial ruin that was Henry's sex lecture.
Trapper has some fun with the kids he's vaccinating, some of whom are almost too savvy even for him. He also manages to help a local farmer save his cow and her calf when the mother is delivering breach, a feat for which he is paid in said mother's milk.
Hawkeye explains to his father about the not-so-secret love affair between the gung-ho uptight Frank Burns and the all-too-military Margaret Houlihan. Through a series of devious and even cruelly escalating pranks, Hawkeye and Trapper manage to bring down not only their morale, but Houlihan's tent around their ears. Pierce later makes up for this in his own way by giving Margaret the Christmas kiss of several lifetimes, which enrages Frank and stuns Margaret.
Hawkeye, dressed as Santa for the orphans, jokes and preps for the kids with volunteer elf Trapper. But Henry and Radar bring news of a soldier wounded on the front lines, with a chest wound best seen to by Pierce. Hawkeye gives Trapper a cautionary "Merry Christmas" if the worst should happen, but McIntyre refuses the grim but tender gesture, saying they'll talk when, not if Pierce comes back. Flying to the front lines in the Santa suit, Pierce's odd appearance is a welcome surprise to both the wounded soldier and his buddies.
The episode ends with a sweep of the cast at that time matched with the actors' names, ending with Hawkeye himself.
- Hawkeye jokingly mentions to his father getting thrown out of the service by wearing women's clothing. Ironically, this is one of the only early episodes featuring Klinger in which he is not dressed in drag.
- This is the first of many episodes framed by a letter (or tape) home written by a cast member, including another Christmas episode, "Dear Sis".
- This is the only Christmas episode featuring Henry Blake, Trapper John, and Frank Burns.