Fifteen of the competition's fiercest challengers return to face-off in the toughest season yet. A mise-en-place challenge set at the Griffith Observatory in Los Angeles kicks off the battle, where the Chefs size each other up since last competing.

This week the chefs honor the late, great Pulitzer-Prize winning food critic Jonathan Gold. Using Gold's last guide list, the chefs fan out all over Los Angeles to sample the unique cuisine only found in the City of Angels.

Comedic superstars Ali Wong and Randall Park swing by the Top Chef kitchen for a Quickfire Challenge tasking the chefs to make the wackiest fried rice they can.

Kelly Clarkson drops into the Top Chef kitchen for a Quickfire based on her new movie, Trolls: World Tour, where the chefs are tasked with combining colorful ingredients from six different musical 'lands' to make one delicious dish.

In the Quickfire, it's a true test of communication as the chefs play a game of telephone with their loved ones.

Padma gets a real rise out of the chefs when she tasks them to make a Quickfire dish without any All-Purpose flour.

The chefs are challenged to a taco throwdown for the taco king, actor and restaurateur Danny Trejo.

It's Restaurant Wars and this season Padma takes all the limitations off the table as the chefs can make as much food as they want and shop wherever they choose.

The chefs head to the mountains, a few hours outside of Los Angeles to go to Summer Camp where they are challenged to an outdoor grilling Quickfire for Padma and "Top Chef" Kentucky winner Kelsey Barnard Clark.

With only six chefs remaining, the challenges get even more difficult, when pastry super-chef Sherry Yard awaits the all stars for a dreaded dessert Quickfire; chefs endure a blindfolded taste test to pick their ingredients.

Tom makes his final decision from "Last Chance Kitchen" on who should return to the competition; the chefs take off in a Quickfire with Padma and Jonathan Waxman making a two-course business class dish for an airline.

The final five travel to Italy, where the chefs must make an aperitivo for 30 locals from the town of Lucca that pairs perfectly with a Peroni beer; then, they hunt the elusive white truffle which they must use in a dish for a Tuscan food festival.

The chefs are treated to a culinary dream trip to Parma, the legendary home of Parmigiano-Reggiano cheese and Prosciutto di Parma ham; the chefs must feature the ingredients in two courses and serve their dishes to a table of 16 Michelin stars.

The final three all stars face off in an epic Italian showdown. They have to cook the meal of their lives in an effort to take home the ultimate title and prize.