The Birthday was the 29th produced episode and the 30th broadcast episode of the television series Joe 90.
Joe 90 reaches the age of ten, and looks back over the most exciting and remarkable year of his life.
It is Joe's birthday but everyone seems to have forgotten about it. Mac is going out, Mrs. Harris apologises for not sending Joe a card, and he begins to feel very sorry for himself. His father returns but still doesn't seem to remember and calls the unhappy Joe into the Dining Room. There to his surprise he finds a huge birthday cake and Mac, Sam and Shane waiting to greet him. Joe is ten years old and over their tea, they reminisce about all that has happened over the last exciting year. Each in turn tells the story of one of Joe's missions for W.I.N. and in exciting flashbacks we remember them, too. At the end of the day the toast is Joe 90 W.I.N.'s Most Special Agent.
No new guests appear in this episode, as it was made up with the following flashbacks: