In a distant future, Tetsuro a human boy who wants his body replaced with a robotic one. This is possible, but to do so he has to reach the Immortal Planet onboard the space train Galaxy Express 999.
An oddly shaped planet complete with giant life-forms appears in the 999's path. Though they have the desire, the planet lacks the desire to move and the 999, unable to escape, sinks into the planet.
S1E51 24 min