BioHeidi is a member of the Laplace Defense Corps (ラプラス防衛隊) which was formed one day after a thunderstorm, when the members found traces of something dragging itself through the forest only to discover an injured Laplace.
Heidi acts as the leader of the Laplace Defense Corps and they were afraid of letting adults know where Laplace as because they thought Pokémon Hunters and Pokémon Merchants might want to capture it. They finally agreed to let Nurse Joy (Kalos) examine Laplace after Ash and Clemont convinced them that Laplace could die if it was not properly treated.
Despite their love for Laplace and wanting it to be around them, the Laplace Defense Corps helped it return to its home after it had been separated by a large rock blocking the river to the sea. After fending off Rocket Gang, Laplace was safely returned to its friends thanks in part to the Defense Corps efforts and they hoped it would visit them again when it was nearby.