SPOILER ALERT! This article contains details of tonight’s fall season finale of ABC’s Grey’s Anatomy

The sound of a hospital getting hacked is the cacophony of flatliners, beeps and buzzes, and tonight’s winter finale of ABC’s Grey’s Anatomy was loaded with it all, leading to a cliffhanger that had the life of an adorably precocious sick kid hanging in the balance.

Written by William Harper, directed by cast member Kevin McKidd and titled “Out of Nowhere,” the last episode until January left the good docs and patients of Grey Sloan Memorial teetering on the edge of disaster.

The episode got truly underway once this week’s patients were diagnosed and prepped for surgery – a nice lady’s spleen removal, the brainy kid with a blood disease, an aging dad with heart problems.

Then the hospital’s monitors and computer screens began their noisy freak-out, never a good sign in an emergency room.

As the stunned docs looked on, their computer screens fill with messages from a hacker demanding beaucoup bitcoins. $20 million, roughly.

As the various pieces of electronica begin to fail one after another, and the FBI works to crack the case, the doctors go back to the medical Stone Age, paper in clipboards, eyeballs instead of camera scopes. Lines start forming alongside the only working CT scanner, but who goes first? The precocious pre-teen or the dad with a family? “Human poker,” says Justin Chambers’ Dr. Alex Karev.

“We need to pay off some Cheeto-stained pirate nerd,” says Chandra Wilson’s Dr. Miranda Bailey.

ABC/Richard Cartwright

Not all went wrong. The middle-aged pregnant woman endures a drug-free but happy-ending labor. A helicopter ride turned very bloody but seemed to get righted. And the still-besotted Arizona (Jessica Capshaw) and Carina (Stefania Spampinato) seem to be heading for a reunion, never mind interloper Owen (Kevin McKidd).

But that sick kid? He was just about to get an incorrect injection that would cause him to bleed out, and the needle-toting Dr. Karev can’t be warned off because of the failed communications – and because Camilla Luddington’s Dr. Jo Wilson, who alone carries the valuable info, is stopped in her tracks with the surprise arrival of her long-gone abusive husband, played by Glee‘s Matthew Morrison.

Morrison’s unexpected appearance in the halls of Grey Sloan sends Doc Jo into some sort of shocked, dreamy reverie, just when she needs to be sharp as that needle that’s about to pollute the sick kid’s already bad blood.

And with that, fade to black, until Thursday, January 18, when Grey’s Anatomy returns to the ABC line-up.