We should have seen it coming. We've had a few light-hearted episodes of Grey's Anatomy, so it was time for an instalment that would leave us on the verge of tears at all times and with our hearts inching up into our mouths. It was devastating, with little light relief - and what's more, it's the last episode of 2011. What a way to go out for the year.

We begin with Teddy and Henry, who you'll remember is coughing up blood. Teddy's ushered him to the hospital, and the doctors buzz about trying to treat him as Teddy sobs. When Webber arrives, he decides they have to go up to CT, despite Teddy's suggestions. But she agrees that Webber knows best, and asks to accompany him to the scan.

Elsewhere, a boy's about to come in with half his face torn off by a dog (we get a shot of that later in the OR, and it's not a pretty sight). But that's not all - a baby born at a nearby tiny hospital is having trouble breathing, and she needs to be picked up.

That calls for Alex, who's in the bar with Meredith and Cristina getting knocked back by pretty ladies (though not drinking). But Meredith leaves when she gets a call from social worker Janet, while Cristina is getting paged.

They all head over to the hospital, but when Cristina finds Meredith later, she's got some bad news. They've lost Zola. It's not confirmed yet, but Janet said the court date has been cancelled which either means they love Meredith and Derek and will call Janet to say so, or they hate them and are giving Zola away. And Janet hasn't had the call.

Meredith explains that Janet said they should consider moving on from Zola, as she holds back tears, trying not to cry (she's not the only one. I'm betting the majority of viewers were blinking away wet eyes, too). But Arizona's telling Alex about the baby at the other hospital - and says he should take Meredith with her. Yep, that's exactly what she needs right now.

Cristina runs to find Derek, who bustles over to see Meredith before she gets in the ambulance with Alex. He's got all sorts of plans - they'll appeal, they'll sue, there's got to be a way - but Meredith is resigned. She doesn't want another baby - Zola was their daughter and she's gone.

Hairstyle, Shoulder, Eyebrow, Eyelash, Brown hair, Long hair, Service, White-collar worker, Job, Nurse uniform, pinterest

That's not all that's going on. Callie's discharging a patient who just had spinal surgery, though she'd like to keep her in for another day. But the patient, Laura, is keen to get home to her son, Drew, and her husband Griffin, and she's putting a brave face on the pain. That would be fine, but after saying goodbye to her surgeon Jackson, she's suddenly crippled over with pain and April rushes over to help. They take her into the OR, and it's soon clear there's a problem with her heart - they need Teddy.

Teddy is currently preoccupied with talking to Henry before his CT, apologising for her reaction to his medical school dreams and promising to be his study buddy. It's so adorable seeing them together (obviously to make the inevitable more painful). Anyway, she soon gets paged but Webber promises to find her when the film comes in. But when he sees the scans, he doesn't look happy.

Callie's shocked to see Laura in the OR - why's there a problem with her heart? But when Teddy arrives, they move Laura upstairs for surgery. On the way into the lift, Webber catches up with her and hands her the scan, but they disagree on the best procedure for Henry - Webber's never done a laser, um, thing (again, I am not a doctor). So Teddy says they should get another surgeon - she wants Cristina to do the operation.

The other doctors aren't convinced - it's too much pressure for Cristina. But Teddy says Cristina doesn't have to know it's Henry if they drape his face and just give a verbal history. Teddy says the only thing she wants is to do the surgery herself but that's not possible - the next best thing is Cristina. So Webber agrees and promises to supervise. Meanwhile, Owen prepares Lexie - Cristina must not know it's Henry on the table.

Teddy speaks to Henry on the phone, and it's more loving chat (heartbreaking, in other words). Meanwhile, Henry tells Lexie he wants to go to medical school and admits that he fought with Teddy about it. Lexie says that doctor-doctor romances are hard... leading to an awkward moment when she has to confess she's not dating either Mark or Jackson now.

Meanwhile, Owen goes to tell Cristina about the procedure, but Cristina isn't thrilled - she's just done one of those and she's got a big procedure to prepare for. She reluctantly agrees to do the surgery, but she's all cocky and unfeeling (classic Cristina, in other words). Her attitude continues in the OR - all she cares about is beating her best time for the operation, and Webber and Lexie have to play along so she doesn't realise what's going on.

Owen watches nervously from the gallery, and when Henry's pressure drops, he rushes down to help. Cristina insists that she's sorted it all out and tells Owen to leave her alone. But is it alright? Is it really?

Meanwhile, April and Teddy begin treating Laura but April catches her glove on something, and when she pulls her hand out, there's a hole in it. In fact, they discover a screw poking into Laura's heart. Callie's pulled straight into the OR to explain herself (not that she really can).

Callie goes to confront Jackson, who performed the operation under her supervision. Then they have to go and tell Griffin, before Callie orders Jackson to order every possible scan to find out what went wrong - if Laura survives. But really Callie's the one feeling guilty - she was reading a magazine when Jackson performed the procedure. Bailey tries to reassure her - it could have happened to anyone - but Callie is devastated.

Back with Henry, and it's all going wrong - he's bleeding and they can't stop it. Cristina discovers that his tumour has eroded through the pulmonary artery (like I said, I'm no doctor, but that doesn't sound good). She doesn't know what else they can do, but Webber determinedly pumps Henry's heart until finally, 20 minutes later, he gives up and Cristina calls the time of death.

It is devastating, and even more so because Cristina doesn't know why Lexie's fled in tears or why Webber is so upset. All she wants to ensure is that Webber makes clear she didn't propose the treatment plan, as that would be a bad outcome. There was nothing they could do, though - the tumour had foxed them before they started. Webber is still absolutely silent, and Owen arrives, gesturing to Cristina. We don't hear what he says, because we just get music. But Cristina is devastated, and screams and cries and collapses onto her husband. Just awful.

And as if that wasn't heartwrenching enough, Owen goes to see Teddy, who's still working on Laura. Unable to interrupt a bypass, he has to pretend that Henry is alright, as Teddy babbles on happily about her relationship with him and their medical school row.

Owen is feeling awful, but Webber insists that he has to keep up the pretence. Owen worries that Teddy will never forgive him, but Webber replies: "Her husband died in our OR. She'll never forgive any of us." So Owen has to return to the OR, claim that Henry's doing well, and listen to Teddy burbling on about Henry some more. Truly devastating.

That's not all, though. Alex and Meredith head over to pick up the baby, as Alex tries to convince Meredith that it's not all over. She could get a surrogate - hell, Cristina's pretty fertile. But Meredith remains stubbornly resigned to losing Zola (we don't get proper closure to all this, by the way, so I'm not convinced Zola's properly out of the picture yet).

Derek's worried that Meredith will blame him - he was the one that pushed her to have kids. He did this to her. But for now, Meredith has to focus on the newborn baby at the other hospital. She and Alex rush in, but there's a problem - the hospital has almost no neo-natal kit (seriously, it's kind of embarrassing how under-equipped it is).

Jackson, Derek, Mark and Arizona get to work on the kid with the ripped up face, but are interrupted when Alex calls for advice about the baby. Arizona warns them they don't have much time, so they start taking the baby to the ambulance. But they're stopped by the girl's mother, Dana, who's desperate to come with them.

"She's my baby," she cries. "We're supposed to be together. I can't leave her, she's so little." Yes, yes, we all get the Meredith parallels. But Meredith promises Dana that she will take care of her until Dana can come and visit in Seattle. And they take the baby out into the ambulance in the rain, thunder and lightning (yep, the weather isn't so subtle. But we'll forgive it).

As they travel, Alex continues to badger Meredith about having kids - he feels like it's his fault that she lost Zola as he snitched on her. As they continue to argue, though, the ambulance stalls. The driver comes out and explains he'll run back to a store to get help, but they have to get out of the back - if anything hits the ambulance, the oxygen tanks will explode. But Alex and Meredith are determined not to leave the baby.

They call Jackson and he takes the phone into Arizona, who's still in surgery. Derek suggests that Jackson should order a helicopter, and he and Arizona continue to speak to Meredith and Alex over the phone. Mark says one of them, at least, has to get out of the ambulance and Alex tells Meredith to go, but she refuses. As they squabble, though, there's a crash - they're thrown around the ambulance in slow motion.

In the OR, it's silent as everyone stares at the phone which has lost the connection. Mark tells Jackson to take over from Derek, who's shellshocked and teary. It's really a very affecting scene indeed. Luckily for us, Meredith and Alex wake up in the ambulance. Meredith decides the best plan is to swaddle the baby in blankets and get her out somehow.

They have to hurry, because the ambulance could still explode, but they manage it (part of me thought it might blow with Alex still inside, but thankfully that's not the case). But the horror isn't over when they get out - they discover a car tipped on its side and bodies strewn across the ground. It's horrific... and we have to wait until 2012 to see what happens next. We're feeling nervous... are you?

What did you think of the episode? Leave your comments below!