Grey's Anatomy › Season 5

S5 E17: I Will Follow You Into the Dark

Name: I Will Follow You Into the Dark
Released: 2009-03-12

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."

Air date	Mar 12, 2009
Runtime	43 minutes
TMDB rating	★ 8.4/10