The 999 lands in complete secrecy at the Tomorrow Planet, whose inhabitants have no knowledge of space travel. One of them learns of the train and steals Tetsuro's pass.
At the City of Night, a dangerous dinosaur named Heron lives in a nearby lake. Tetsuro discovers the animal is in fact friendly, but will he be believed?
The 999 arrives at the Pitch Dark Planet, a world that is about to experience its first ever artificial sun... which will doom it, unless Tetsuro can stop it.
The 999 arrives at the Planet of Silence, a quiet world where everyone speaks softly and listens with special devices... the better to snoop around on each other.
The 999 arrives at a planet where the people are starving because their Queen orders all food to be brought to her. But there is a dark, tragic secret behind her appetite...
The C62 locomotive that pulls the 999 threatens to disconnect and power ahead on its own. At the same time, news is received of two dangerous robbers aboard the train.
The 999 arrives at the River of Purgatory, a barren region under progress to become fertile. A son wants to leave the world, but can he leave his father behind to do all the work?
The 999 arrives at the Gimme Planet, a world where everybody is a beggar. Two bandits however rebel against this way of life and attempt to escape on the train.
On the Hangman's Planet of cowboys, a feud starts between the White and Black gangs over a gold mine. Tetsuro ends up in the Blacks, and his new friend Wester joins the Whites.
The 999 arrives at the ice planet Snowica. Tetsuro encounters the famous ramen cook Tsuru, and the fearsome Snow Woman whose freezing spree is forcing people to mechanical bodies.
The 999 passes through a loose zone where everyone becomes lazy and irresponsible. Tetsuro ends up stranded on a garbage planet, but everyone is too loose to search for him.