Tom sells Jerry to a local pet store that's buying white mice. Yes, Jerry's brown, but a little paint fixes that.

John and his class go on a school trip to the Tower of London. While he is there he loses his pet mouse and vows to return and find her later. Back in school, he is not very attentive and falls asleep during a lesson about electricity so his teacher sends him home. On the 'tube' there is a sudden flash, and John, the train and all of the passengers turn yellow. With the help of Nick (short for 'Electronic') John learns about electricity, invades the Tower of London and saves his pet mouse ... or was it a dream. This is the Powell & Pressburger touch applied to children's films.

A salaryman sees a murder in the subways and is soon pursued by the killer, who wants him to join a group called The Engineers, who have taken it upon themselves to reduce Japan's overpopulation. Despite not wanting any part of joining, the man begins to mutate, running throughout Japan and fighting his urge to kill.