2x19 - The Lost World

Marguerite and Roxton are enjoying an intimate moment, when suddenly the earth moves! They find themselves sprawled in the bottom of a pit, with a pirate's skeleton and his cursed treasure chest filled with a fortune in booty. Unimpressed by a little curse, Marguerite takes it to the Treehouse. Challenger and Malone find the pirate's journal, and decide to unravel his story. Traveling to the described inland sea, they are ambushed by pirate descendant Pappin, who seizes the journal. He sends his men to find the treasure, then shackles Malone in a tidal cave, leaving Challenger tied up in his shack