The surgeons work as a team to free a boy from a hardening block of cement; Izzie helps Alex care for an ailing Rebecca; Meredith and Derek have one last chance at a positive result in their clinical trial.
Jack is torn between Emily and the new woman in his life, while Nolan and Louise bring Southern charm to East Hampton.
Now that Emily Prentiss has returned, the unit track down a serial killer hiding out in the woods before he can strike again.
The death of Picard's archaeology professor results in a tantalising mystery involving Klingons, Cardassians and Romulans.