第 12 集: Lunar 向 Nagasumi 尋求課業輔導，卻在輔導期間意外變成美人魚。
2007年6月18日 播出
Sun and Nagasumi's mom leave the house to go shopping for groceries, leaving Lunar alone with Nagasumi. Lunar aims to make Nagasumi tutor her, since she is failing all her subjects. It is then that Maki witnesses the two seemingly flirting with each other, even though they both deny having feelings for each other. Lunar then accidentally spills water on her legs, converting her in mermaid form. Unfortunately, Lunar's Papa shows up just as Nagasumi finished drying her rear end to revert her back, thereby giving the wrong impression. Ultimately, Nagasumi's life is spare after Lunar confesses her newfound feelings for him, and, in turn, Nagasumi winds up being engaged to Lunar. (Source: Wikipedia)
集數
- 第 8 集 · Nagasumi 提議舉辦歌唱比賽，以解決涉及 Maki 的日益升級的校園衝突。
- 第 9 集 · 患有懼廣症的人魚美佳·川原挑戰長瀞，爭取太陽的婚約。
- 第 10 集 · 強悍男子尾隨Nagasumi，Sun介入調停，Gouzaburou則與Lunar的父親展開激戰。
- 第 11 集 · 五藏郎的禮物意外導致巨大化
- 第 12 集 · Lunar 向 Nagasumi 尋求課業輔導，卻在輔導期間意外變成美人魚。
- 第 13 集 · 長瀞拒絕包辦婚姻，太陽介入並表白愛意
- 第 14 集 · 長瀞帶貓去學校，發現朋友們對貓有嚴重恐懼
- 第 15 集 · 長瀞在雙重約會事件中與班長相遇
- 第 16 集 · 美人魚考官白羽天乃測試太陽應對非人型美人魚的能力。