Doraemon goes missing for days, and when he turns up he explains why: he has been queuing in the 22nd century for tickets to the Galaxy Super-Express, a mystery train that never announces where it is going. Nobita Nobi, Shizuka Minamoto, Suneo Honekawa, and Takeshi Gouda board with him and arrive at Dreamers' Land, an enormous amusement park planet split into western, fantasy, ninja, and dinosaur worlds. While they are enjoying the rides, parasitic aliens called Yadori begin taking over the visitors one by one.