By the end of shift four, the remaining chefs will have been cooking for 12 consecutive hours. To make it to hour 13, Michael Symon and Esther Choi present their toughest task yet -- teamwork. Working with chefs they just met mere hours ago, the competitors have to strategize, collaborate and execute under the critical eyes of guest judges Michael and Bryan Voltaggio.

As hosts Michael Symon and Esther Choir introduce hour 18 of non-stop cooking, the chefs are bruised, battered and at their breaking point. Simplicity is one of the most difficult techniques to master for any chef, and when they're this exhausted, it borders on impossible. Guest judge Brooke Williamson decides which four chefs will receive a spot in the finale, a mere four challenges and three hours away.