Preview of 'Grey's Anatomy' 6.04: Tainted Obligation

Lexie pleads Meredith to save their father's life when he is in desperate need of an organ transplant and a lot of blood.

In the preview for "Grey's Anatomy" October 8 episode, a flash back to Meredith's dark past is given. When Meredith and Lexie's father, Thatcher, returns to the hospital with a failed liver, it's up to Meredith to save his life because she is the one who has his blood.

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. Jeff Perry returns to his role as Thatcher Grey in the episode called "Tainted Obligation".

Meanwhile, the merger is still creating quite a stress for the staff of Seattle Grace Hospital. Recently it was confirmed that at least four staff from Mercy West Hospital are coming to work with them. The new characters are played by Robert Baker, Jesse Williams, Nora Zehetner and Sarah Drew.