Mario stumbles through three Japanese fairy tales like he wandered into the wrong storybook and nobody bothered to rewrite the script. The incoherence is the point, watching familiar characters operate in logic that doesn't hold together creates a specific kind of fascinating wrongness that only exists in this exact artifact, from this exact moment in anime history. This is what happens when a toy company experiments on IP with zero regard for coherence, and the result is stranger than anything intentional.
Three short OVAs released only in Japan in 1989 recast familiar fairy tales with the cast of the Mario games. Each episode runs roughly fifteen minutes and retells one story: Momotaro, Issun-boshi, and Snow White. Mario, Luigi, Princess Peach, Bowser and the Koopalings all take part, turning the old tales into lighthearted fantasy adventures with plenty of comedy. Because the release never left Japan, the set is very hard to find elsewhere.