Doraemon: Nobita's Three Visionary Swordsmen.

Nobita is exhausted from having constant nightmares and pleads Doraemon to arrange a dream machine that will enable him to dream of anything he wishes for. As Nobita dreams of him and his friends in the roles of gallant musketeers, the dream world starts to break down due to a dark force, and Nobita will have to put his fantasy to the test and become a hero, both in the real world and imagined.