Hotaru resolves to become a changed woman given her new status. She is determined to become thrifty, save, dress appropriately and make herself worthy of her promised future. Who is the woman and child visiting the house and calling her manager and man 'papa' though? Her co-worker misses her period and may be pregnant. Hotaru organizes a children's event and ends up going for a meal of Iberian pig not when she anticipated, where she thought or with whom she planned.
蛍（綾瀬はるか）は高野（藤木直人）に節約もできない女とは結婚できないと告げられ、節約を始める。そんな中、蛍が担当する商店街主催のキッズフェアが資金難で中止に。蛍は、お金を掛けない方法で開催できるよう、企画を練り直すことに。一方、瀬乃（向井理）が企画案を出していた総予算20億円のプロジェクトが流れてしまう。
因為小螢（綾瀨遙飾）不懂得節制節省，存款餘額只剩47圓，高野部長（藤木直人飾）要她學習節約，不然就不跟她結婚。
發誓要節約的小螢，正在籌畫小朋友嘉年華。這個活動因為經費不足，原本要喊停，但在小螢熱心的規劃，和精簡經費的情況下，終於可以舉辦。身為商店街會場的肉店老闆，看到小螢這麼熱心，於是提供伊比利黑毛豬肉當小朋友競賽第一名的獎品。
當小螢知道部長喜歡吃伊比利黑毛豬肉後，便決定參加小朋友競賽，決心要替部長贏得第一名的獎品…
