Previously: Science was the death of Hugh Acheson, while Mary Sue Milliken prevailed with her culinary exemplification of viscosity. Four chefs and $100,000 remain.

The remaining chefs pile into the kitchen. Floyd Cardoz, in particular, is embarrassed that he has made it this far without winning any challenges. For this week's quickfire, the chefs will be blindfolded as they man work stations divided in two. They have to make a dish in 20 minutes while simultaneously instructing a mystery sous chef to make the exact same dish. Each chef is outfitted with the same tools and ingredients. Curtis Stone will judge the final results. Mary Sue's mystery sous chef is her sister Chris DeWitt. Traci Des Jardins' is her brother Mitch. Floyd's sister Debra Furtado will assist him, and Naomi Pomeroy's father Toby will act as her sous chef.

The chefs immediately recognize that their helpers are not culinary students but are stumped as to who they are. Mary Sue decides simplicity will be her best asset, and Naomi goes with that old standby -- bacon. Never one to avoid a challenge, Traci goes for a halibut dish, while Floyd also tackles seafood with a stir fried shrimp. Naomi has the most trouble with her sous chef and quickly dissolves into a virtual banshee. Mary Sue and Floyd have a lot better time of it as the clock ticks down. Naomi continues to rail on her father unknowingly, worried that he won't manage to plate her dish before the time runs out.

The clock finally lapses, and Naomi is first to discover her mystery guest. She is suitably embarrassed, though her dad says her behavior was nothing out of the ordinary. She presents her fricassee of mushrooms, bacon, and shallots with a poached egg and parsley. Curtis is impressed how close her father's looks, though the seasoning isn't exactly the same. Floyd is next to discover his sister behind the divider. The two shrimp, mushroom, and asparagus stir fry dishes don't look all that similar, though Curtis likes the taste, especially the crunch of the asparagus. Mary Sue is reunited with her sister Chris next. Their dual shredded chicken salads with toasted crumbs and sesame seeds are both deemed delicious and aesthetically pleasing. Finally, Traci discovers that she's been working with her own brother. She is pleased that her halibut with asparagus in brown butter balsamic vinaigrette looks exactly the same as Mitch's. Curtis jokes that he doesn't know whose dish he likes better. Ultimately, it's time to decide a winner. Curtis says he liked Naomi and Traci's dishes the best, though Traci gets the edge (and $10,000 for her charity) on this particular challenge.