It all starts with an invitation to a birthday party. The invitation bills it as the biggest, bestest, hattiest party of all time. Unworried by his hatless state at first, our young protagonist sets off but without success. He cannot find a hat anywhere. Undeterred, he cleverly finds a monkey with a hat to accompany him and off he goes. You would think this would be it, boy brings hat to party, end of story. The protagonist hadn’t reckoned, however, on a doorman who seems to have no other wish in life than to stop him entering his friend’s birthday party.