Chapter 6

The sixth Crystal Star is in the Poshley Sanctum of the town Poshley Heights. The only way to reach the town is on the famous Excess Express. After doing Don Pianta another favor, he gives Mario the train ticket.

On the first day at the Excess Express, Mario and his team found many mysterious happenings, including thefts of items and messages threatening to blow up the train. On their second day of travel, Pennington, a Bumpty detective, helps Mario and his friends to solve the crimes and they manage to capture a fake Zip Toad who was really Doopliss in disguise, and was the one who attempted to halt the train by causing an explosion with some stolen items. At sundown, when the train stops at Riverside Station for refuel, Doopliss escapes capture. Mario and company find that the drawbridge has been lifted, preventing the Excess Express from continuing its route. The gang enters Riverside Station and flips the switch to bring the drawbridge back down. They discover that a group of Smorgs are behind it. On the third and final day of the journey, a stowaway Smorg monster attacks the train, kidnapping all of its passengers. Mario and his friends defeat the creature, rescuing the passengers in the process, and finally reach Poshley Heights. They venture into Poshley Sanctum, a museum that happens to belong to Pennington. The Shadow Sirens happen to be already inside, and snatch what appears to be the Garnet Star and run away. However, Pennington reveals that what they stole was a fake, and lets Mario find where the real Crystal Star is. After some exploring, Mario and company manage to find the real Garnet Star.

Back at the X-Naut base, the X-Nauts tell Grodus that Mario has six of the seven Crystal Stars. They also tell him of TEC's betrayal. Meanwhile, TEC tells the Princess the data he gained from Grodus's data disk, and prepares to help Peach escape. Before he is able to, Grodus enters with two X-Nauts and orders them to initiate the data-wipe procedure. TEC tells Peach "I love you" just before he is shut down.

Meanwhile, Bowser is searching for another Crystal Star in Rawk Hawk's workout room, which he has found in the form of the Champ's Belt. However, he quickly learns that it is not a real Crystal Star, just a glass fake.

Mario and his team return to Rogueport and receive an e-mail from Peach, telling about what the X-Nauts plan to do with her, but an important part of it is cut off due to TEC being shut down. Back in Rogueport, Mario and co. reveal the next Crystal Star's location and visit Prof. Frankly for details.