The Lost World (1999)

S3E21 Trapped

What begins as a serene day of adventure quickly turns perilous when an unexpected explosion ensnares Marguerite and Roxton in a subterranean chamber. Their only chance of rescue lies with Challenger, but the blast has robbed him of his identity and memories of his companions. Simultaneously, a playful competition between Veronica and Finn leads to a mysterious find at the Treehouse, unearthing a fragment from Veronica's past. As Roxton and Marguerite grapple with imminent danger, they confront feelings long suppressed, risking their budding relationship even if they manage to survive.