Newbery honor book: 1975.

Mario, Luigi, Princess Toadstool and Toad have ventured to Robo Land in pursuit of King Koopa, whom they had intended to stop. However, after finding King Koopa, Mario and his friends soon find themselves running for their lives, as Bullet Bills are being fired in their direction continuously.

In the Wild West, Mario, Luigi and Toad begin to search for Princess Toadstool, who has been kidnapped by Kid Koopa and taken into the Wild West. While traveling through the desert, Mario and Luigi notice a wanted poster on a nearby cactus with a hat on it. Looking at the wanted poster, Toad notices that its Mario and Luigi displayed on it and the reward for their capture is 10,000 gold pieces.

In Victoria, Mario and Luigi are riding atop a carriage being pulled by a horse traveling down a street in search of a great detective by the name of Herlock Solmes, with Toad and Princess Toadstool riding in the carriage.

In Pirate Waters, located in Pirate World, Mario and Luigi are in the middle of peeling potatoes onboard a ship. As he peels potatoes, Mario remembers how he, Luigi, Toad and Princess Toadstool came to be on this ship; while traveling to Princess Toadstool's Castle, Mario, Luigi, Toad and Princess Toadstool were hired as the crew of the only ship willing to sail Pirate Waters.

In an island owned by King Koopa, King Koopa has kidnapped Princess Toadstool again and is holding her in his island fortress.

In the Snow World, Mario, Luigi, Toad and Princess Toadstool, exhausted and hungry, weakly venture forth through a snowy field, mentioning that the hoards of Koopa Khan are after them. As he walks forward, Luigi suddenly falls and begins to be blown through the air by the powerful wind of the Snow World, with Princess Toadstool, Toad and Mario being blown-away with him.

Mario, Luigi, Princess Toadstool and Toad have found King Koopa's secret summer castle, where they have been captured in the courtyard, each with ball and chain shackled to their ankle.

n the Amazon Jungle, Mario, using a plunger to swat his way through a variety of flora, leads Luigi, Toad and Princess Toadstool in their search for Dr. Sheldon, a mysterious witch doctor. After swatting through a large wall of bamboo, Mario, Luigi, Toad and Princess Toadstool find themselves in a large clearing, with Mario inquiring if he can stop and take a lunch break.

Princess Toadstool has been captured by Captain Koopa, who is now racing down the river of the River World in his ship, the Sinister Star. As Captain Koopa paces back and forth near the steering wheel of the Sinister Star, First Mate Mouser appears from below deck to report that he has found no trace of any stowaways. Not satisfied with this, Captain Koopa violently shoves First Mate Mouser aside and ventures below the deck of the Sinister Star.