George has had his turn, as has Alex, so this week the voiceover duties go to Izzie. Although it's not voiceover, exactly, since she's actually saying these things to someone as she lies in bed, extremely pasty and extra sick-looking and with a pink patterned head scarf, she does set the theme of this week's episode. And who could she possibly be speaking to? Well that's just a surprise for now, unless of course you have ever watched TV before and can guess these "twists" and/or saw any promotional pictures or anything about this landmark 100th episode. "You never know the biggest day of your life is going to be the biggest. The days you think are going to be big ones, they're never as big as you make them out to be in your head.

In a slow-mo close-up we see Bailey's hand fluffing a wedding gown, and another of the woman fixing the strap. Izzie continues, wheezing a bit, "It's the regular days, the ones that start out normal -- those are the days that end up being the biggest. And today was the wedding. It was beautiful, perfect." After some shots of the beautifully decorated church and the guests standing up to see the bride (even though we don't get to see her) we cut to Meredith and Derek standing in the not-yet-decorated church by themselves. Meredith says it's just a normal day; they are going to work and then afterwards they just happen to be getting married in a, "churchy church..." her voice is now annoyed and Derek jumps in to remind her that this has nothing to do with them. "We're just the bride and groom." But Meredith then lightens up and smiles as she says, sounding genuinely pleased, "We're getting married tonight," which he repeats. 100 episodes in, Meredith seems to really have grown into a happy, optimistic person.

Callie is sleeping on a couch in the hospital when she's woken up by an incredibly peeved Cristina, who is upset to find her there since she herself slept in the on-call room instead of at home in her own bed. Her mood was not great to begin with given that she has to work a full day and then, "be happy Maid of Honor and get Meredith down the aisle." So, I guess while viewers can see the changes in Mere, those around her haven't quite gotten how real it is. Apparently Callie asked Cristina to stay away because she thought it was going to be The Night with Arizona, but she tells Cristina that they went to dinner but she then wasn't in the mood, and also she had to be in early to run the ER. Cristina asks, laboring to sound casual, if Hunt isn't in but Callie says that he is and then runs off. Mere then walks in and Cristina puts on her best cheerleader face and rah-rahs, "Big day! Biggest day of your life!" Mercifully, Mere tells her to stop because she's being creepy. Cristina is relieved, but then immediately suspicious that this is just the calm before the storm and asks if she is going to need to drug Mere, or "shave off [her] eyebrows to numb [her] into submission?" Meredith assures her best friend that she is fine, and that she's excited about the marriage, not the wedding. Today is actually the biggest day of Izzie's (possibly short) life. She reminds Cristina that Izzie is the one who has gone bridezilla and Cristina repeats, "Bridezillllaaaaaaaaa," in a hilarious horror-movie voice. It's a total throwaway moment, but it's awesome.