In Pokémon Diamond and Pearl, the player's rival can be found in the entrance chamber, complaining about having been defeated by Buck. Within the main cavern, the player encounters Buck, who is hunting for the Magma Stone and decides to accompany the player to the entrance to Heatran's room. Inside, Buck takes the Magma Stone and leaves.
In Pokémon Platinum, Charon takes control of Team Galactic and travels through Stark Mountain to take the Magma Stone and capture Heatran. Mars and Jupiter are both encountered in the entrance chamber, each battling the player. Within the main cavern, Buck teams up with the player, looking to protect the Magma Stone from Team Galactic. Once the player follows Charon to Heatran's room, Looker arrests Charon and takes the Magma Stone. Buck then returns the Magma Stone after he and the player accompany Looker outside.
After the events at Stark Mountain are completed, if the player speaks to Buck's grandfather in the Survival Area, he will tell them about Heatran. In Diamond and Pearl, it is at this point that Buck returns the Magma Stone to its original location. Heatran then appears in its room, ready to be battled by the player.
Stark Mountain's exterior changes between Pokémon Diamond and Pearl and Pokémon Platinum. The road ascends in a huge contour up the mountain and, at that point, Route 227 ends and the exterior of Stark Mountain begins. In Pokémon Diamond and Pearl, a huge clearing opens up that contains a large patch of tall grass. The entrance to the interior of the mountain can be found to the west.
In Pokémon Platinum, the exterior is more complex and the path winds around pools of bubbling lava. It is darker and aesthetic features have been enhanced. The large patch of tall grass is still present, but it is not as big. By going northwest, an item can be found in an indented section of track. By traveling to the northeastern corner, a path will open up. By following it, the road will lead through two pools of smoking, bubbling lava around another bend to the entrance of the interior of the mountain.
In Pokémon Diamond and Pearl, Buck can be found inside the main cavern on the player's first visit. He is searching for the Magma Stone and, due to the strong Pokémon in the area, asks to team up with the player.
In Pokémon Platinum, Buck is initially encountered on Route 227 after the player crosses the eastern fallen log. He asks them to investigate a bunch of goons in space suits who are up to no good at the mountain while he returns to the Pokémon Center to heal. After the player enters the main cavern of Stark Mountain, Buck returns and asks to accompany the player.
Buck is one of the Stat Trainers, specializing in the Defense and Special Defense stats. While he is with the player, all wild battles become Double Battles, and all Trainer battles that would otherwise be Double Battles become Multi Battles. After every battle, he will completely heal the player's party. He leaves the player once they have reached the entrance to Heatran's room.
Stark Mountain appeared in The Magma Stone. Buck arrived at the site too late to prevent Charon from awakening Heatran, and was soon joined by Looker, who was seeking to arrest Charon. Although Looker managed to knock Charon unconscious and Buck successfully restored the Magma Stone to its proper place, thus resealing Heatran, Charon managed to get away with the help of his two underlings.
After hearing Looker talking about Team Galactic's activities at the mountain, Buck departed for the volcano, intending to protect Heatran from the villainous team. Upon reaching the volcano in Interrupting Ivysaur, he decided to call his brother Flint, who told him about the Magma Stone hidden inside the deepest part of the volcano. Having noticed a group of Galactic Grunts following him, Buck attacked them and demanded information from them, but when he failed to get any answers from the mute Grunts, he decided to simply find the Magma Stone first. With the help of his Claydol, Buck soon found the room with the Magma Stone. Thinking that the Magma Stone was what Team Galactic was after, Buck tried to take it away, only to unwittingly unseal Heatran, which was then caught by Charon.
Alerted by the earthquakes caused by Heatran's awakening, Looker traveled to Stark Mountain to help Buck, and managed to interrogate Charon long enough to learn that he was collecting the Legendary Pokémon of Sinnoh in preparation for his attack on the Distortion World, where Giratina lives. Charon managed to escape soon after, while Looker and Buck only barely managed to get away thanks to the help from Platinum's Pokémon, although not without being severely injured.
In Gathering of the Legendary Pokémon!, Charon returned to Stark Mountain. After his attempt to obtain Giratina had failed, he decided to settle for Heatran, only to be confronted by Looker, who arrested him and informed him that Cyrus had officially disbanded Team Galactic.
Related cards Cards listed with a blue background are only legal to use in the current Expanded format. Cards listed with a silver background are legal to use in both the current Standard and Expanded formats.
This is the only location in Sinnoh that is not a route where the player can rematch a Trainer using the Vs. Seeker, as Dragon Tamer Darien is outside and thus in an area where the Vs. Seeker can be used.