: Jeffrey Dean Morgan makes a final appearance as Denny Duquette, appearing as a hallucination to Izzie that Derek and Bailey eventually realize is a symptom of her worsening condition. Behind the Scenes Facts
While the wedding takes center stage, the hospital remains in chaos due to a tragic car crash involving college students on their way to graduation. [S5E22] What a Difference a Day Makes
The episode's central plot twist occurs when Meredith and Derek decide to give their meticulously planned wedding to Izzie and Alex. : Jeffrey Dean Morgan makes a final appearance
: After Derek and Bailey discover that Izzie has an inoperable brain tumor, the group decides to celebrate her life and love immediately. : After Derek and Bailey discover that Izzie
: Despite the shift in plans, the wedding remains a fan favorite, featuring the original "MAGIC" interns (Meredith, Alex, George, Izzie, and Cristina) as the wedding party.
: Creator Shonda Rhimes noted that Denny's appearance in this episode was meant to represent "Death," which is why he wore black and spoke sparingly compared to previous appearances.