Rise of the Mushroom Kingdom is a series of 4 YouTube videos. Chronologically it takes place after Mario and Luigi Bowser's Inside Story and Super Mario Bros Z Part 1 and Part 2 was a dream. Part 3 and Part 4 was the actual adventure.
The night before the adventure Luigi had a dream that his brother Mario died when he was attacked with 3 bullet bills and a Banzai Bill. In the Dream Luigi and the citizens of the Mushroom Kingdom thought that Bowser was behind the murder so they invaded Castle Koopa. The Toads and Yoshi's attacked a bunch of Koopa Soldiers and Luigi battled Bowser on the roof. He eventually threw Bowser far away. Bowser was eaten by newborn Yoshi's and died. When Luigi was back at Mario's grave he saw that King Wart III was actually behind the murder.
After Luigi woke up
Luigi woke up when 3 bullet bills and a Banzai Bill passed over him. The dream was a vision of things to come! Wart III was seeking revenge on Mario for killing his father Wart II in BS Super Mario USA. He retrieved a stopwatch and froze time so he could move Mario out of the way. He managed to do that but then the stopwatch stopped causing the bullet bills and Banzai Bill to strike him. His legs blew off. Luigi explained that Wart III was behind it. He then died with only one 1up mushroom left. Mario was mistaken that Luigi had GAME OVER so he got really angry. He grabbed a cape feather and flew trough a door to the Kingdom of United Creatures. After defeating Mouser in a battle, in the castle Clawgrip stole his cap making him furious. After throwing Clawgrip into Boiling Water he then battled Wart. During the battle, Mario threw a vegetable into Warts mouth. Wart accidentally swallowed it. The reason why Wart hated Vegetables was because it gave him gas. Wart suddenly had a gas attack. He was so embarrassed he ran out of His castle. Mario chased him. After Wart was forced up to the roof of the castle, he trapped Mario in a bubble, which then floated past the edge of the castle to be popped by a pelican. Mario fell down the side of the castle toward a pile of spikes. Seeing this must be his destiny, he prepared for the worst. As Mario fell closer and closer to the spikes, a person all of a sudden swooped in a saved him, taking him up to the roof. His savior was none other then Luigi himself. As the two reunited brothers fought Wart, eventually they defeated Wart. As fireworks exploded and the Toads celebrated. King Koopa became the king of the KUC.