Kakushite! Makina-san!!

Season 1, Episode 6: Thus, Makina Is Taken

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Makina, whose mechanical identity must remain a secret, frantically calls Mamimi from her apartment to explain away the commotion caused at school. During the call, she starts making odd sounds due to Eita's ongoing maintenance, but somehow manages to keep her cover until the end. Just as things settle down, a mysterious girl suddenly appears at their apartment...