The Penguin Spirit appears again and tells Shōma and Kamba to board a train and find a girl named Ringo Oginome who may possess the Penguindrum. With Ringo attending a girl's school, Shōma and Kamba send in their penguins to follow her. The brothers end up following her to a lingerie store, where they spot her maneuvering round the outside of a building in order to take a photo of something, which she shows to the brother's teacher, Mr. Tabuki. She then follows him home and hides out under his house, where the brothers conclude that she is a stalker, and pulls out a diary which allegedly fortells destined events.
L'entità del cappello di Himari dà a Shōma e Kanba un indizio per la ricerca del Pingdrum: Ringo Oginome è la probabile custode dell'oggetto e potranno incontrarla sulla metropolitana.
陽毬を生かしたければ、生存戦略のため「ピングドラム」を探せ、と冠葉と晶馬に迫るペンギン帽子。
妹の命を盾に取られた２人は、「ピングドラム」が何かもわからないまま、指示された電車に乗車する。
そして、「ピングドラム」を所持している可能性がある荻野目苹果という少女の後をつけ、彼女の身辺を探るのだった。
