This is the first chapter of Paper Mario: The Mystical Artifacts.
Chapter 1: Gloop Gloop Trouble
-Gloop Bloop Village
Mario and his new partner, Bianca, reach Gloop Bloop Village, a small village located near Gloop Gloop Lake. Most inhabitants here are friendly Bloopers. As they walk around the village, the duo begin to notice that the villagers seem afraid of something, so they decide to ask some of them about what's going on. The villagers tell Mario that the lake is being terrorized by a mean Big Blooper, who isn't letting anyone, not even other Bloopers, swim in the lake. A few days ago, a young Blooper named Bloobo and his sister, Bloorianni, were playing in the lake, when suddenly the Big Blooper showed up and kidnapped Bloorianni. Bloobo tried to rescue her, but he was no match for the Big Blooper. Seeing that the villagers need help, Mario decides to go defeat the Big Blooper and rescue Bloobo's sister.
Just as they're about to leave the village, though, Bloobo shows up and asks Mario if he could come along, since he wants to rescue his sister and get revenge on the Big Blooper that kidnapped her. Mario lets him join the team. With this, Mario and co. leave Gloop Bloop Village.
-Gloop Gloop Pathway
On their way to the lake, Mario and co. fight some Goombas and Koopas and also use Bloobo's ability to get through some obstacles. At one point, they are stopped by a familiar enemy: Bowser. He says that he's tired of Mario always ruining his plans, so he decided to just get rid of Mario once and for all. With this, Bowser attacks.
Mini Boss: Bowser
After Bowser is defeated, he says that this isn't over yet and runs away. Mario and co. just continue on, and soon they reach the lake and dive into it.
-Gloop Gloop Lake
In the lake, Mario needs to watch his air meter, which can be re-filled by air bubbles (they are all over the lake). Eventually, Mario and co. reach a small temple known as Gloop Gloop Ruins. Bloobo explains that this is where the Big Blooper lives, so that means that Bloorianni must be inside this place too. Unfortunately, there seems to be no way to get in, as the front door is locked. Bloobo says that the Big Blooper must have locked the front door to prevent anyone from invading his hideout, so Mario and his friends decide to explore the lake some more and try to find a way to get inside Gloop Gloop Ruins.
Eventually, the trio find an underwater cavern, which they then go in. Inside, all they find is a switch, but just as Mario is about to hit it, a Big Urchin appears and attacks the group.
Mini Boss: Big Urchin
After defeating the Big Urchin is defeated, Mario hits the switch, which unlocks the front door of Gloop Gloop Ruins. With this, Mario and co. enter the ruined temple.
-Gloop Gloop Ruins
Here, the heroes solve many puzzles and battle some new enemies, such as Cheep Cheeps, normal Urchins and Hermite Crabs. After lots of puzzles and fights, Mario and his friends reach the end of the ruins, where they find Bloorianni locked inside of a cage. Bloobo tries to free her, but then the Big Blooper appears and attacks the group.
Chapter 1 Boss: Big Blooper
After the Big Blooper is defeated, it drops the key to Bloorianni's cage, allowing Bloobo to free his sister. As the two are having a heartwarming reunion, Mario notices that the Big Blooper dropped something else, which turns out to be the Ancient Bracelet, one of the Mystical Artifacts. It seems that the bracelet made the Big Blooper powerful, which explained why it was stronger than normal Big Bloopers. So, with this, Mario grabs the bracelet and everyone leaves the ruins.
-Gloop Bloop Village
Bloobo tells Mario that the village's mayor will be taking care of Bloorianni, since the young Blooper wants to help Mario on his quest to defeat the Skull King and become a stronger Blooper. With this, Mario and co. return to Toad Town.
Merlon congratulates Mario for getting the Ancient Bracelet and tells him that the next artifact, the Light Crystal, is located in the Icicle Caves. So, with this, Mario and his new friends leave the town and go to their next destination.
End Of Chapter.