Galaxy Express 999 Season 5 Episode 16 Keiko of the Insect Planet

There are warnings about mysterious murders taking place on the Bug Planet. After arrival, Tetsuro and Maetel come across the murder scene of a business man. It seems that the key to the murders is a girl named Keiko who supports the bugs' cause and has sided with them. She then quickly asks Tetsuro if he'd become a bug-man to help save the planet's insects. Then, some very tiny bug-men appear in front of Tetsuro.