Handsome Harry hires Charly & Co to follow a man called Mr. Ritter who works as gym personal trainer. Fred joins the gym as undercover agent and discover his beloved Ms. Stratford is training there with him. There is a series of accidents in the gym working area involving the bio teacher, but Fred saves her ¿ by chance ¿ becoming a local hero. The kids suspects Ritter as the saboteur. In addition, Charly becomes jealous of Fred's protagonism and even fires Fred from the Agency!