Jon and Tom's parents go away on vacation, leaving the two boys in the care of their strange Aunt Dahlia. On the first night of Aunt Dahlia's stay, she whips up a batch of strange prune cookies. Suspicious and disgusted, but not wanting to insult their aunt, Jon and Tom eat all of her prune cookies (finding them surprisingly delicious), as well as a dinner with prune sauce. Their suspicions of strange Aunt Dahlia prove warranted the next day, however, when they see the side effects of the prune cookies!