Infinity On High

Meredith sighs; gosh, as if this day weren't hard enough without it being the start of the clinical trial while her and McDreamy are now on the fritz.

And to add to all of that, Derek Shepherd's ex-wife is in town, and she's still all hot and leggy and fabulous, and now her hair is a shade darker, and a tad longer, and all in those cool waves that must match the ones washing over the Los Angeles ocean.