: After Derek and Bailey discover that Izzie has an inoperable brain tumor, the group decides to celebrate her life and love immediately.
The episode's central plot twist occurs when Meredith and Derek decide to give their meticulously planned wedding to Izzie and Alex. [S5E22] What a Difference a Day Makes
: To promote the 100th episode, ABC created a real wedding website for Meredith and Derek that fans could actually visit and RSVP to. : After Derek and Bailey discover that Izzie
