Bertha is a cute seven-year-old second grader who attends an all-girls boarding school in the US state of Maine. She loves swimming as it's a subject at her school, which is why she always wears her pink swimming goggles on her eyes and her long-sleeved swimming shirt and short-sleeved swimming togs under her school uniform. She is really friendly and cheerful, and she has 15 other girls in her class, all of whom love swimming as much as her.