Steeplechase Hen III (S03E07)

It turns out that the secret experiments that the Kudou Family has been conducting was for developing parasite dolls, a female combat robot possessed by a parasite. Experiments on the dolls' operations are being conducted at the Steeplechase Cross-country venue, where security is abnormally tight - so much so that Tatsuya himself can't even break into the premises. As such, Tatsuya orders Pixie to keep an eye out for the parasites while he conducts adjustments to the CADs and gives instructions to the underclassmen as an engineer. However, this continual sense of nervousness and nonstop days of hard work are tiring out Tatsuya. He's never felt this tired before. (Crunchyroll)