There's more than one Dr. Shepherd roaming the halls of Seattle Grace at the moment. That's because Amelia (guest star Caterina Scorsone) left sunny California seeking help from her big brother. Derek won't even consider operating on his sister's friend, Erica, so Amelia calls him a jackass. Lexie can't help but crack at this.
Lexie convinces Derek to let Amelia practice a procedure she needs to complete in 90 seconds if there's any chance of saving Erica. The dry runs don't go well, but a more difficult plan may actually be more efficient. Derek softens a bit once he realizes that Amelia is stronger than he thought. They work together get the procedure down to 86 seconds. That'll work! They'll be operating on Erica in the "You Break My Heart" episode of Private Practice.
The fifth years are busy prepping for the oral boards. Jackson and April are study buddies. Alex is using his intern, Morgan, to quiz him. Meredith should be studying with Cristina, but she's too busy trying to save her marriage in therapy with Owen. After a clandestine meeting with Richard, Callie considers letting Mer in on her secret study method. She must first prove herself worthy by leading the case involving a man who got his arm stuck in a meat grinder.
The patient's buddies work to take apart the meat grinder. They pass out the moment they complete the job. The arm looks like it can't be saved until Meredith remembers reading something about using a patient's toe to repair a thumb. It's the only way to save the entire arm, and it was all Meredith's idea. Her reward is access to Callie's secret study methods.