Nogizaka Haruka's Secret

The Secret Between the Two of Us (3x4)

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The episode starts with Setsugetsuka Tennōji, who is a rival of Haruka, gloating over being able to hurt Haruka. Yūto decides to go to Haruka and stop her marriage, and is aided by Mika and the maids. His classmates, sister and teacher all join him on the plane to where Haruka is held. Everyone but Yūto and Mika sacrifices themselves to fight the "Hellhounds", while Haruka defeats someone guarding her. Yūto has to fight Haruka's father, while Haruka has to fight her mother to prove their love. They proceed to embrace each other. Haruka's rival steps in, summoning the Tennōji clan's knight, who has already been dealt with by Tōka Tennōji. Haruka and Yūto then get married.