Meredith and Derek get one last shot at success in their clinical trial; the surgeons work together to free a boy from a block of cement; Izzie helps Alex care for Rebecca; Lexie uncovers critical information about George's status as an intern.
The team investigates a string of ritualistic murders that could be linked to the Salem witch trials. Meanwhile, Garcia prepares a celebration for the Day of the Dead.
After construction workers find an archbishop's body with the kneecaps surgically removed, the team returns to the case of the Widow's Son serial killer.
When a young man comes into the hospital severely burnt and has unusual blood-test results, House and his team have a difficult challenge.