Season 5 • Episode 17
I Will Follow You Into the Dark
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2009-03-12
★ 8.3
43 min
Derek decides to quit after learning that more of his patients have died than survived; Izzie's interns make an unsettling discovery about "Patient X."
Guest Stars
Jessica Capshaw
Loretta Devine
Gloria Garayua
Mark Saul
Wendy Hoopes
Erin Cahill
Michael Rady
Candice Afia
Nicole Cummins-Rubio
Molly Kidder