The reference to a "" in your query likely refers to a specific plot point in this episode: Vivian Charles spots an advertisement in the newspaper for a synchronized swimming act called the "Aquaberries," which prompts her and her sister Lily to come out of seclusion. Episode Details
: Vivian sees the ad in the paper while she and Lily are alone on Chuck’s "half-birthday". [S2E13] Kerplunk
: Ned and Chuck investigate a murder involving a rival synchronized swimming duo (the Aquadolls vs. the Aquaberries). Meanwhile, Lily and Vivian (the Darling Mermaid Darlings) face their past when they decide to perform again. The reference to a "" in your query
: Because the show was canceled, this episode had to "race through plot threads" to provide some closure, though it famously ended on several unresolved cliffhangers. the Aquaberries)