However, the Beheeyem are spotted outside the village, forcing the player and partner to flee to Lively Town, the site of the Expedition Society headquarters. Upon arriving, Ampharos inducts them into the Expedition Society and introduces them to the other members: explorers Archen, Bunnelby, Buizel, archaeologist Mawile, astronomer Jirachi, communications officer Dedenne, and cook Swirlix. After a few days of work, Archen invites them to a trip to the Air Continent, where they discover that a malicious entity has been turning Pokémon to stone. The Society initially assumes Entei is involved after Latios and Latias are found turned to stone, but when the player and partner inexplicably evolve to their final forms and defeat him, they realize he was only investigating the current events. A few days later, the entity confronts Entei. Although the Society is unable to prevent Entei from being turned to stone, they find evidence that implies that Krookodile, a local thug, is the culprit. When it is found that a dungeon called the Prehistoric Ruins may help them find more answers, the Society initially intends to go, but the player and partner hear that Krookodile is headed towards Serene Village and leave with Archen to intercept him. Nuzleaf meets up with them and informs them that Krookodile was heading up Revelation Mountain and joins the chase. At the top, the group discovers a sealed spring that can return petrified Pokémon to normal. They confront Krookodile, but Nuzleaf, along with the legendary Pokémon Yveltal, petrifies the group, dries out the spring water, and begin attacking Pokémon around the world. Ampharos, Jirachi, and Espurr manage to survive while everyone else the player knew is turned to stone. During this time, the player wakes up in a world called the Voidlands and is reunited with most of the Society. As they try to find a way back to their world, they discover that the planet's life source, the Tree of Life, was once pulled toward the sun by the entity, now known as Dark Matter, but was stopped by 'the alignment of the stars'. However, they are attacked by manifestations of the Voidlands' darkness. Raikou, Entei, and Suicune save the player, partner, and Mawile, but the others are incapacitated. They make their way up Reverse Mountain, the only way out of the Voidlands, but the battle at the top is so fierce that the player and partner's allies have to sacrifice themselves to let them escape.