There, the crime-fighters attempt to foil Lord Marmaduke Ffogg and his sister Lady Penelope Peasoup's plot to steal priceless treasures with the aid of a fog-creating pipe.
The pair take the Batmobile on the boat and set up a temporary Batcave at a country manor house that Bruce Wayne rents.
Batman goes to the Three Bells pub, Robin is accosted and kidnapped by Prudence and her gang of female thieves, and Barbara realizes the true nature of the school.
After changing into her Batgirl outfit, Barbara finds the stolen treasures at the Ffogg estate, but is captured by paralyzing gas released by Prudence.
Ffogg throws lethal fog pellets into his dungeon to finish off the trapped Batgirl, but Batman arrives and rescues her.
Ffogg, Peasoup, and Prudence are arrested; Batgirl disappears followed by Barbara conveniently appearing soon afterward; and the Americans return home.
Finally, while the campy humor of Batman gives something of a pass for unrealistic situations, DeCandido felt that even given that, the plot of the episodes made no sense.