Tonight, ABC will be showing the one of the best episodes of Season 3 at 9 p.m. In "Six Days (Part I)" and Part II, Meredith battles her past and her abandonment issues as Thatcher Grey returns to the hospital with Mer's half-sister Molly and her infant daughter. Meanwhile, Derek battles insomnia as Meredith snores. Loudly.

Elsewhere, George's father survives his heart surgery, but the procedure to treat his cancer proves futile and puts the O'Malley family in a difficult place. Alex and Addison get closer as she pushes Mark away. Preston recovers from surgery, but repairing things with Cristina is another matter. Izzie and Callie, meanwhile, treat a patient who is literally bent out of shape.

For a complete rundown, check out our episode guides to Part I and Part II, list of memorable quotes, list of music and image gallery from each episode. You can discuss, along with all things Grey's Anatomy, in our forum!

Follow the jump for a terrific two-minute clip from Part I - the concluding montage featuring Travis' "Love Will Come Through" - as well as a fun clip of Burktina from Part II.