As young children, the two were the best of friends. Together, they attended Counting School, Counting Camp and were partners in the Counting Scouts. But she and her parents moved to Melbourne, Australia, separating her and the Count. Over the years, they have reunited, treating each "Hello" as a precious moment in their friendship (and another thing for them to count). They then immediately exchange goodbyes (in a variety of languages), knowing that the sooner they depart, they sooner they can get together again. The episode shows their 103rd time performing this ritual.
Her name is a reference to the Australian song "Waltzing Matilda."