Kakushite! Makina-san!!

S01E07 Thus, the Sisters Swap Places

Makina finds herself stripped of her physical form, as her younger sister robot, Mimika, takes over. Makina describes Mimika as an agent-type robot adept at feigning vulnerability to emotionally sway those around her. To locate the elusive Mimika, Eita suggests a plan that only a genuine mecha enthusiast could come up with.