Timmy is forced to go to Vicky's little sister's birthday party, and, unfortunately, she likes Timmy. Cosmo has the fairy flu, where fairies temporarily lose control of their magic. Wanda also catches it; they wreck havoc at the birthday party until Timmy manages to feed them lots of sour curate, which cures them. Unfortunately, Timmy caught the sour curate allergy, and Vicky's little sister comes over to cheer him up.