Welcome to KoreaEdit
"Welcome to Korea" was the 73rd episode of the M*A*S*H television series, and first episode of the fourth season of the series. First aired on September 12, 1975, the series' first 60 minute episode (double the normal time) was most notable for its off-screen departure of the character of Captain Trapper John McIntyre (played by Wayne Rogers), and his replacement by the freshlydrafted Captain B.J. Hunnicutt (played by Mike Farrell).
"Welcome to Korea" features the first depiction of the 4077th MASH following the death of former unit commander Lieutenant Colonel Henry Blake (formerly played by McLean Stevenson), and with Major Frank Burns (played by Larry Linville) in charge. Another change of command is previewed, in the form of a short appearance by Harry Morgan as Colonel Sherman T. Potter; he would be fully introduced in the following episode, "Change of Command".
The episode, which was written by Everett Greenbaum, Jim Fritzell, and series creator Larry Gelbart and directed by Gene Reynolds, won two Emmy awards in 1976: "Outstanding Directing in a Comedy Series" for Reynolds, and "Outstanding Achievement in Film Editing for Entertainment Programming in a Comedy Series". After the joint departures of Stevenson and Rogers, one third of the original cast, after the series' third season, there was a great deal of uncertainty about the direction and future for the series; "Welcome to Korea" was notable for beginning a generalized move for the series away from a dark comedy to a dramedy.
The episode opens with the raising of the United Nations and American flags at the 4077th MASH. Quotes from American general Dwight D. Eisenhower and Raymond Bliss are superimposed on the screen, including:"I will go to Korea."—Dwight D. Eisenhower, 
In a scene often cut in syndication, Major Frank Burns (played by Larry Linville), who since the previous episode has been the new commanding officer of the unit, enters Corporal Radar O'Reilly's office early in the morning and finds him still asleep. Burns then proceeds to wake Radar, angry that his company clerk failed to wake him for morning roll call, as is custom in theArmy. After an exchange regarding O'Reilly's non-standard filing system in the office, the two go leave into the main compound. As the two walk to the tent of Major Burns' mistress and second-in-command, Major Margaret Houlihan (played by Loretta Swit) in preparation for the roll call, the episode's credits are displayed on screen.
Radar then plays assembly and the company falls in. After the company has assembled, Burns takes issue with a number of things, including the time it took to assemble and a woman's hat that Corporal Max Klinger is wearing, and a ham stolen from his office. Burns begins to make some announcements to the camp, but, at this point, a rickshaw arrives, carrying Captain Hawkeye Pierce, returning from a week of R&R.
Defying Burns' authority, Pierce ignores the assembly ceremony, mockingly "checks in with the commanding officer" with the line "Hi, honey, I'm home" and presenting Frank with a doll of General Douglas MacArthur. Ignoring Frank's orders, he walks into the showers fully clothed in an attempt to shake off the hangover he acquired while in Tokyo. After dismissing the assembled camp, Radar follows Hawkeye into the showers to inform him of Captain Trapper John McIntyre's military discharge during Hawkeye's R&R; he has left the camp only hours before Hawkeye's return, without leaving a written goodbye.
Meanwhile, in the commanding officer's office, an eager Houlihan and Burns are looking forward to the arrival of Trapper's replacement, Captain B.J. Hunnicutt. Hawkeye, still wet from his shower, enters the office demanding to go to say goodbye to Trapper; Frank denies this request, greatly angering Hawkeye. Radar then enters to request and subsequently receive permission to pick up Hunnicutt at the Kimpo Air Base in Seoul, the same place at which Trapper is departing that morning. Hawkeye, still angered at Burns, storms out of the office. Houilhan, while reading the new surgeon's file, notes that he is fresh out of residency and remarks that "we'll train him our way, Frank."
Just as Radar is preparing to leave in a jeep for Kimpo, Hawkeye jumps in, demanding to drive; Radar at first refuses, due to the trouble he could get into. Eventually, though, Radar gives in and two drive off.
Hawkeye and Radar arrive at Kimpo Air Force base; Hawkeye heads for the MATS office, while Radar attempts to find the replacement surgeon. Inside the MATS office, the sergeant in command is on the phone attempting to straighten out an order of odd foods and items for a general. Hawkeye, though initially unsuccessful in gaining the sergeant's attention, is eventually able to obtain a copy of the day's stateside manifests, only to find that Trapper's flight was ten minutes ago. Disheartened, he leaves the office.
Radar finds Hawkeye standing outside the MATS office, still disappointed, and introduces him to the new surgeon - Captain B.J. Hunnicutt. Hawkeye and Radar decide it is time to leave, but their jeep seems to have been taken. Radar panics - he is worried what losing a jeep will look like on his record. Hawkeye calms him down and suggests they all go to the officer's club to unwind. However, as Radar notes, the club is for officers only. Hawkeye quickly devises a solution - he takes one of Hunnicutt's sets of captain's bars, and pins them on Radar's hat. Radar inquires how the corporal's stripes on his jacket can be explained, and Hawkeye replies that he is testing a new rank - corporal captain.
Hawkeye, B.J., and a frightened Radar enter the officer's club and sit down at the bar. After ordering drinks (two bourbon and water, and a grape Nehi for Radar), B.J. begins to talk about his family, his draft and training. During the conversation, Radar notices that a colonel in the back of the club has been looking at him strangely. Eventually, the colonel approaches the three, inquiring about Radar's strange combination of corporal's stripes and captain's bars. Hawkeye, using a great deal of army babble, explains that it is an experimental rank, and they are gathering opinions on the new rank. The colonel expresses that "I don't like it. I don't like it at all!" B.J. notes the colonel's negative expression, and the colonel leaves. Hawkeye and B.J. wrap up their conversation, pay for their drinks, and decide to leave and try to find another jeep.
Outside, Radar encounters a general and his aide, who easily terrify him because of his self-consciousness about his fake rank. Hawkeye and B.J. step out of the officer's club, and Hawkeye spots the general's jeep. He attempts to convince Radar that the jeep is the one they had stolen, merely disguised as a general's jeep. He tosses off the flag (indicating that the jeep belongs to a general) and jumps in, attempting to drive, although Radar convinces him not to because of the alcohol he just consumed in the officer's club. Radar throws his hat (carrying B.J.'s captain's bars) at Hunnicutt, and drives off.
At around the same time, at the 4077th, Frank Burns is talking to Father Mulcahy (played by William Christopher) about giving an obedience lecture because he claims that the camp has no respect for him. Houlihan enters and interrupts the conversation. She asks Frank if he gave Pierce permission to leave camp, because he appears to be AWOL. Frank answers in the negative, and a short argument ensues. Father Mulcahy insists that the Captain must have a good reason to be gone, and Frank sharply tells the Father to keep out of his business. Houlihan insists that Burns apologize to the Father. Frank does so to both Mulcahy and Margaret, hastily saying, "Sorry, Father. Sorry, Mother," which gets a raised eyebrow from the chaplain.
On the ride home, B.J.'s hat flies off, but Hawkeye expresses little concern about this, saying, "Your cookies'll be next." The Jeep drives by a local farm. Hawkeye sees two Korean woman doing something strange in a wheat field, and an older man standing by. He orders Radar to stop the Jeep, gets out and begins to berate the old man, who is allowing his daughters to check for land mines in the field. Hawkeye states this is very dangerous and tells the man he is "oo-san (Korean 우산)". Radar taps Hawkeye on the shoulder and informs him that he just called the man an umbrella. At that moment, an explosion is heard in the minefield. Heedless of the danger, Radar rushes in to help the wounded woman out of the field, over Hawkeye and B.J.'s urgent entreaties. He carries the woman out of the field unhurt, and they put her on the Jeep to transport her somewhere she can receive medical attention. At this, the rest of the family tries to climb on the Jeep, over Hawkeye's protests. When the farmer attempts to bring his ox on the Jeep, Hawkeye, not knowing Korean, asks Radar to tell the man "No ox! No ox!" Radar dutifully shouts "No ox! No ox!" at the old man in English. As they drive off, Hawkeye commends Radar on his bravery in disregarding the mines. Radar, for the first time realizing the danger he'd been in, exclaims in wonder, "Wow, that was brave." 
Later, a tire blows on the Jeep and they stop to fix it. While the tire is being replaced, the men find themselves being targeted by sniper fire. They change the tire as quickly as possible, but Radar refuses to abandon the tire jack, stating, "This is a general's jack!" "Salute it and get in!" Hawkeye replies sharply, and Radar instinctively does so before realizing his peril. He hops in the Jeep with the others and drives off.
A little further down the road, the three run into an army patrol in the wake of battle. Hawkeye and B.J. get out to assist in aiding the casualties. As B.J. goes to help one soldier, he slips and falls in a muddy ditch, ruining his dress uniform. Moments later, he starts towards another casualty, but Hawkeye says the man is beyond help. Insisting on trying, B.J. turns the man's body upright, but is horrified by what he sees, stumbles away, and vomits. Hawkeye goes to assist B.J., giving him a hand to help him up.
Almost at the end of their journey, Hawkeye insists on stopping at Rosie's Bar just outside camp. He takes B.J. inside and buys him a drink; Radar has his usual Grape Nehi. Hawkeye describes the work B.J. will be doing at the 4077th and the general atmosphere of the camp; "Pitch in, muddle through, pip-pip and the whole smear." Meanwhile, a fight breaks out between two of the other patrons, and they fall on Hawkeye and B.J.'s table, shattering it. Hawkeye blithely regards them: "Please! I'm with friends."  A while later, a drunken Hawkeye and B.J. stumble out of the bar. Once again, Hawkeye tries to insist on driving but Radar refuses.
Frank and Margaret hear an approaching Jeep; very excited, they prepare for Captain Hunnicutt's arrival. They go outside and meet the Jeep as it drives up. B.J. and Hawkeye manage to unevenly scramble out of the Jeep as Hawkeye introduces B.J. B.J. salutes Frank, then bursts out with, "What say you, Ferret Face?" and collapses on his knees, clasping himself to Margaret's legs. Frank and Margaret look on with aghast horror as Hawkeye collapses in hysterical laughter. Later Burns is arrested by MPs for driving the General's jeep that Hawkeye had "borrowed".
At the end of the episode, the cast of M*A*S*H is shown, with one addition - Colonel Sherman T. Potter. In what is presumably the next day, Radar is sitting outside shirtless, holding a metal sheet in front of him to reflect the sun. An older officer drives up in a Jeep and honks the horn loudly several times to announce his arrival. Radar, not looking at the man, snorts, "Stick that horn in your ear." The older gentleman announces himself as Col. Sherman Potter, new commander of the 4077th. Radar scrambles to recover as we fade to closing credits. The date is given as September 19, 1952.