Grey's Anatomy

Tainted Obligation

Aired Oct 8, 2009 · 9:00 PM ET · 43 min

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.