For his next mission, Robert goes to Sesame Place in Langhorne, PA, to help celebrate Sesame Street's 40th birthday. Robert meets three of the Sesame Street's most famous residents (and his helpers for the day) - Elmo, Cookie Monster and Maria. The three special guests give Robert his mission. Robert must make a meal for 250 people in just eight hours and , in honor of the big birthday, everything on the menu must start with the letter "B." Using just one letter is a funny way to make a meal and so is watching Elmo and Cookie Monster try to help Robert in the kitchen. One of Robert's big challenges is turning regular B ingredients into A plus food. With help from Maria, he transforms plain baloney into a gourmet kids' treat. He makes a ton of dishes using berries, beans and beef. Robert even bets that he can make Elmo's least favorite food - Brussels sprouts - taste wonderful. But when things start to heat up, Robert gets serious and the Muppets get out of the way With time running out, Robert's big menu comes back to haunt him in a big way. There are several dishes aren't done, a birthday cake that isn't finished and now there's one big chef who's not kidding around. With 250 parents and kids waiting for the birthday bash, will Robert be successful, or will this be Dinner Impossible?