In Exploring the Dark Cave, Lyra and her Marill were exploring Dark Cave when they accidentally spooked a flock of Zubats causing them to get separated. Marill kept running while Lyra twisted her ankle by tripping over a rock. Marill was then founded by Peter, Harry, and Hobie when they explored the cave. It was scared of them until Peter assured Marill that they won't hurt it. Marill then led the trio to Lyra where they reunited. Lyra then revealed to Peter that she and Marill were together when she was young and chose to join her when Lyra became a trainer. Marill and her trainer then joined Peter's group since Lyra decides that it is no fun to travel alone.