Crayon Shin-chan: Fast Asleep! The Great Assault on the Dreaming World!

A story set in the dream world, depicting the Kasukabe Defense Forces and the Nohara Family fighting against a nightmare trouble. One day the people in Kasukabe come to be able to have dreams they want in their sleep, after having a strange dream in which a giant fish swallows them. The people enjoy having their own distinctive dream in the dream world, but the world gradually changes into a nightmare world. Shinnosuke Nohara and Kasukabe Defense Forces members let Saki Nubatama, a girl who moves in Kasukabe, join the group, and they go into the dream world to explore the cause of the nightmare.

(Source: Manabu Tsuribe)