Watch The Great Food Truck Race Season 15 Episode 4 Online

In Redondo Beach, Calif., special guest food truck and all-star season runner-up Seoul Sausage challenges the teams to craft a game-changing box lunch and sell it on the boardwalk. Sales improve for most of the food trucks, with one truck selling more than they've sold in the entire race. But one team struggles with sales -- and with each other, forcing Tyler Florence to pay them a visit and lead a makeshift therapy session.