Tonight's two-hour Grey's Anatomy-Private Practice crossover event has its work cut out to live up to the amount of hype it's received - but we think it's up to the task.

In tonight's episode, "Before and After," Addison, Naomi and Sam rush to Seattle Grace to save Archer, and in the process, reunite with old friends Derek and Mark.

Meanwhile, in an attempt to figure out what's wrong with her, Izzie employs her fellow doctors in a medical game, and Owen Hunt runs into someone from his past.

Check out the videos and gallery we've posted for previews!

As always, you can discuss "Before and After" before and after (ha!) the show in our

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