Grandpa's sister, Mitzi, shows up out of the blue to grace the boarding house with her presence./When Coach Wittenberg needs to form a synchronized swim team to save his job, he recruits Arnold, Gerald and the rest of the gang to compete.
Grandpa's Sister: Grandpa's sister Mitzi unexpectedly comes over to the Sunset Arms, and Grandpa isn't too happy about it. Synchronized Swimming: Coach Wittenberg talks the boys into forming a synchronized swimming team, though they think it's for girls.