Super Mario World

Super Mario World was the rescue of Dinosaur Land and Princess Peach from Bowser and the Koopalings.

History
Princess Peach, Mario, & Luigi went on vacation to Dinosaur Land. After joyously flying through the land using the Cape Feather and their Cape, they return to their hot air balloon to see Princess Peach missing, leading the Mario Bros. to realize Bowser is up to his old tricks.

Before that happened, the Yoshis and their Yoshi Eggs were first captured by Bowser and the Koopalings. Yoshi tried rescuing his friends but got trapped by Bowser in an egg.

Mario & Luigi started their adventure through Dinosaur Land. In each area, they'd encounter one of Bowser's fortresses, defeat the Koopaling stationed inside, safely escort one of Yoshi's friends outside, and destroy the castle.

After saving a great deal of Dinosaur Land, the Mario Bros. reach the Valley of Bowser, where Bowser awaits. Reaching the top of his castle, Bowser introduces himself in his newly-introduced flying vehicle: the Clown Car. Throwing the Mechakoopas back at him, the Clown Car eventually malfunctions and Bowser flies away. Peach is rescued, and their vacation can now resume as normal.

Throughout their adventure, Mario and Luigi would also accumulate a bunch of Dragon Coins. And after visiting all of what's left in Dinosaur Land, autumn falls and Mario & Luigi spread around masks of their likenesses for Koopa Troopas to wear along with a variety of miscellaneous changes that may or may not be influenced by them.

Timeline

 * Bowser seals all of the Yoshis in eggs and takes over Dinosaur Land, possibly enacting the revenge he vowed in the previous title.
 * Mario & Luigi take a vacation to Dinosaur Land directly after saving the Mushroom World during Super Mario Bros. 3.
 * The Koopalings reappear, placing this game after Super Mario Bros. 3.
 * Mario & Luigi meet Yoshi for the first time.