In Grey’s Anatomy season 11, episode 17, "With or Without You," Derek returns to Seattle to address his near-infidelity with a research fellow while Meredith confronts the instability of their marriage. The episode also features subplots involving Owen’s mother and a unique medical case involving a sinus leech. Read the full recap at TV Fanatic .
"Grey's Anatomy" With or Without You (TV Episode 2015) - IMDb [S11E17] With or Without You