Grey's Anatomy

Season 6, Episode 4

Episode Title: Tainted Obligation

Air Date: 2009-10-08

Overview:

When Meredith and Lexie's father, Thatcher, returns to the hospital with a failed liver, it's up to Meredith to save his life. Meanwhile, Izzie empathizes with a patient riddled with tumors, as Mark, annoyed with Cristina's competitive zeal, tricks her into assisting on an unusual surgery.