Major 'Downton Abbey' shocker devastates the Crawleys -- and fans

Downton Abbey Recap: Bad Medicine

[SPOILER ALERT: This article discusses key plot developments from last night’s episode of “Downton Abbey.” If you don’t want to know what happened, stop reading now.]

Last night was truly bittersweet for fans of “Downton Abbey”: Just as the cast of PBS’s acclaimed period drama was celebrating a surprise win at the SAG Awards, the Crawleys were suffering a terrible loss within the family. This week’s episode saw the youngest Crawley daughter, Lady Sybil, die suddenly after giving birth to Lord Grantham’s first grandchild… and sent fans into a state of mourning online.

The episode originally aired months ago in the U.K., but even if you knew what was coming, you couldn’t help but be affected by last night’s sad events. As Sybil prepared to give birth, two doctors bickered over how to treat her, with family physician Dr. Clarkson saying she needed to go to the hospital to avoid life-threatening eclampsia, and new doc Sir Phillip (with the backing of patriarch Robert) insisting she was fine. Sir Phillip looked to be vindicated when the baby was born healthy. But later that night, Sybil took a sudden turn for the worse, suffering nasty seizures before tragically passing away, with both doctors helpless to save her.

[Related: 'Downton's' Joanne Froggatt Tells Us About Anna's Season 3 Detective Work]

The news of Sybil’s death reverberated throughout the halls of Downton, both upstairs and downstairs. A grieving Cora held her husband Robert responsible for the tragedy, even banishing him from their marital bed. Mrs. Hughes noted sadly, “The sweetest spirit under this roof is gone.” Heck, even the black-hearted footman Thomas broke down into tears after hearing the news about Sybil: “In my life, I can tell you, not many have been kind to me. She was one of the few.”

And “Downton” viewers were reaching for the tissues as well. Vulture called Sybil’s untimely end “unquestionably the most wrenching plot development in the entire series thus far.” Here’s some of the eulogizing offered by fans on Twitter:

How did you react to Sybil’s death? Do you blame Robert (like Cora does)? Let us know in the comments.