The focus of this book is -- yep you guessed it -- Grover's new jacket, sent to him as a gift (is it his birthday? hmmm guess we will never know) by his grandma. Grover is the envy of Sesame Street in his vintage 1980s Members-Only style red jacket, and wears it everywhere to bring him luck at school, playing jacks, etc. He wins the part of the prince in his class's school play and while he works hard to practice his lines, he knows his jacket will bring him the luck he needs to do the part well. That is of course until he loses it backstage right as the show starts, almost has a complete nervous breakdown, and wants to quit the show right then and there. After a pep talk from the ever-supportive Mr. Lester, Grover goes on and does the part beautifully, even without his jacket -- which he is happily reunited with at the end of the book.