The Ranger teens and Ernie plan a surprise party at the Juice Bar for Zack. The secrecy leads him to believe that they have all forgotten about his birthday. Rita shows that she cares–about seeing to it that he never again lives to celebrate any others, that is–by sending down a special treat, a vicious black armored monster known as Knasty Knight. Zack soon finds out he is way over his head. Happy Birthday indeed.