The cast of M*A*S*H didn’t learn of Col. Blake’s fate until just before the scene was shot

Widely regarded as one of the best shows television has ever seen, MAS*H was never afraid to push the envelope. Though a comedy series at heart, the nature of the show’s setting played into the storyline frequently, with life and death situations, life-saving prodecures and very tough goodbyes.

Like any show that has success, there are times when actors want a break from the norm, to pursue other opportuniteis for their career. This was the case for McLean Stevenson, who played the beloved Lieutenant Colonel Henry Blake for the first three seasons.

Not wanting to return for a fourth season on MAS*H, a plot was created to write him out of the show, one that was a surprise to most of the cast.

In an Archive of American Television interview from 1998, producer and co-creator Larry Gelbart acknowledged there was an opportunity, with the character of Blake, to do something that turned heads. Gelbart and co-creator Gene Reynolds both agreed something drastic would play out upon Stevenson and his character leaving the show.

“Gene and I thought that we should use the departure of the character in some meaningful fashion,” Gelbart said.

The storyline up until the end of the episode was a happy one that saw Blake get discharged, allowing him to head back to his family in the States. The producers wanted a more realistic feel to the departure, knowing that not everyone who went to war came home.

“MASH was not about everybody having a good time, MASH was not about happy endings, and we decided that his character could, not should, but could die,” Gelbart said.

Knowing how big of a change this would be for the show, season three’s final episode was titled “Abyssinia, Henry” which is lingo from the 1920s era meaning “I’ll be seeing you,” says Gelbart, who acknowledged the corny meaning behind the title fit well with the character of Henry Blake.

“We assigned the script to a writing team who had done a lot of work for MAS*H,” Gelbart recalled. “We wanted it to essentially be a goodbye episode in which people shared their feelings, no big tension no big storyline and we said we wanted him to die at the end… and we swore them to secrecy.”

The ending that sees Col. Blake killed off was set to be so earth-shattering for the cast, that the producers didn’t tell them their plans. Alan Alda was the only cast member that knew the way Blake was set to be written off the show was via death, in an off-screen plane crash after being discharged.

They kept it a secret by totally leaving out that portion of the script.

“When [the writers] brought the episode [script] in, we detached that page and did not distribute it. We rehearsed the episode, we shot the episode… The reason we kept it a secret was to keep the actors from being influenced by that information. If they started to film the show knowing that Henry was a deadman by the end of the episode, their performances would’ve been quite different.”

Thus, the crew shot every scene prior to the one on the withheld script. The cast was ready to call it a “wrap” on season three of MAS*H when Gelbart informed them they weren’t actually done yet.

“Gene and I took the cast over to one side and sat them down and said ‘look, we’re going to do something that you don’t know about.’ I had this manila envelope with the last page in it that they’d never seen… It’s not often in your life that you see people stunned… They really could not believe what was on the page.”

The cast went back into the studio to film the final scene of season three, where Radar comes into the operating room with a telegram saying, “Lieutenant Colonel Henry Blake’s plane was shot down over the sea of Japan. It spun in. There were no survivors.”

In one of the most gut-wrenching episodes of the series, the cast, including Stevenson himself, didn’t know the fate of Henry Blake. The move resulted in thousands of letters from fans, describing their displeasure with how Blake was written off.

Though it caused headlines, angered fans and saddened Stevenson, so much that he didn’t go to the cast’s “wrap party,” Gelbart stood by his decision to send off Henry Blake the way he went.

“I think it was a very grown up thing to do and very sensible thing to do.”