Ep. 4: Keita visita um resort de águas termais com as garotas após receber ingressos como presente de formatura de seus pais.

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The sibling's parents give Keita tickets to a hot spring resort as a graduation gift and suggest that he take the girls along on the trip. The siblings go to the hot spring resort, end up visiting an erotic museum, and find themselves in some compromising situations involving Ako's unintentional purchase of alcohol. (Source: Wikipedia)