Grey's Anatomy
Episode Stills

This Thursday's episode of Grey's Anatomy, "Holidaze," combines Thanksgiving, Christmas and New Year's - and notably features the arrival of Mark Sloan's long-lost ... daughter.

Yes, a hot, blonde, McSteamy spawn. We'll pause for a moment to let that sink in.

Aside from guest star Leven Rambin (who plays the character from Mark's past, whomever she is), Thatcher Grey and Miranda's as-yet-unseen father also appear in the episode.

Click to enlarge some photos from "Holidaze" below and see what you think ...

Thursday's Grey's Anatomy marks the debut of yet another new cast member, Kim Raver as Dr. Teddy Altman, an old friend of Owen's from the Iraq war and the new cardio god at Seattle Grace-Mercy West. Suffice it to say, Cristina is going to love her!

Elsewhere, Izzie returns to Seattle Grace with her high school mentor, who is seeking treatment for his dementia, and the stress of Richard's job starts to take an even bigger toll.

Click to enlarge some pictures from the episode, "New History" ...

Promotional photos from this week's episode of Grey's Anatomy, "Invest in Love," show the gang in a festive mood. Or are they? Arizona is under a lot of pressure to save a patient.

Yes, that's always the case for a doctor. But one of this patient's parents has a donation of $25 million Seattle Grace may be able to garner. You can imagine how the Chief reacts.

Arizona, along with girlfriend Callie, is front and center in many of the photos below, as are Mark and Lexie. What a cute couple they make. What do you think they're celebrating? 

Click to enlarge the images below and tell us what you think...

This week's episode of Grey's Anatomy features a character we haven't seen much of lately: Derek. McDreamy has been in every episode this season, but rarely front and center.

That's about to change as he fights to save the hospital's own lab technician, Isaac, from an inoperable tumor surrounding his spine. All the while, he battles Richard's authority.

"Give Peace a Chance" also marks the directorial debut of Chandra Wilson (Dr. Miranda Bailey), who steps behind as well as in front of the Grey's Anatomy camera this week.

Click to enlarge photos from this Grey's Anatomy episode ...

Thursday, Grey's Anatomy airs what looks like the most intense episode of its sixth season so far. Entitled "I Saw What I Saw," the episode begins with a burn victim unexpectedly dying in the ER, leaving the Chief scrambling to figure out what happened.

Who's responsible? Who will be assigned the blame?

That we'll have to wait and see, but it's a foregone conclusion that the Seattle Grace-Mercy West rivalry will be ramped up to new levels as the hunt for answers ensues.

Below are episode stills from Thursday's episode of Grey's Anatomy. Click to enlarge ...

This week's episode of Grey's Anatomy, "Invasion," looks like it has been aptly named.

New residents from Mercy West are swarming in on the new iteration of Seattle Grace and vying for jobs. Dr. Izzie Stevens is in for a tough fight, from the looks of the pictures below.

Katherine Heigl's character, who we know is taking a five-episode hiatus this year, can be seen in these images getting in the face of the newcomers and the face of her boss, Richard.

This episode may very well mark her sendoff, but for what reason? Stay tuned there.

Meanwhile, Callie's dad (guest star Hector Elizondo) is back in Seattle, looking to bring his daughter back to heterosexuality. That's not going to work, and should be quite awkward.

Click to enlarge the images from this week's episode of Grey's Anatomy ...

Below are promotional pictures from this week's all-new episode of Grey's Anatomy, "Tainted Obligation." Thatcher Grey is back at Seattle Grace, and he needs a transplant.

Presumably for his liver. Lexie's not a match. That means ... Meredith is likely to devolve into her dark, twisty self as she considers her choice. And we're in for an intense episode. 

Click to enlarge the images below for a little preview of Thursday ...

After an emotional season premiere, the surgeons of Seattle Grace are beginning to settle into their lives post-George. That doesn't mean things have settled down, however.

Below are some promotional photos for tonight's episode of Grey's Anatomy, "I Always Feel Like Somebody's Watchin' Me." Izzie has a wig and there's baseball being played.

How will the doctors react to looming budget cuts? What type of trauma case is Owen handling? Does Cristina understand the statistical implications of the double switch?

Click to enlarge the photos below and see what you think ...

It will certainly be interesting to see the direction this "transitional" season heads now that George is gone. Follow this link for a complete photo gallery from tonight's episode!