Elkan Allen and Charles Hoffman pen The Londinium Larcenies from a story by Allen. The episode launches a three-episode arc that began on 23 November, 1967. It riffs on the idea of the British Invasion, though it’s the reverse this time, as Batman (Adam West) and Robin (Burt Ward) head across the pond (which looks a lot like Southern California) to help out the famed Ireland Yard with a series of thefts around Chuckingham palace.

The thefts are being conducted by Lord Marmaduke Ffog (Rudy Vallee) and Lady Penelope Peasoup (Glynis Johns) aided by lots of manmade fog, provided by Ffogs pipe. They also have a private girls finishing school which is being used to train the students in the fine art of shoplifting.

Gordon (Neil Hamilton) is asked by the President to help their allies across the ocean and he reaches out to Batman and Robin, who in the form of Bruce Wayne and Dick Grayson travel to Londinium with Alfred (Alan Napier), who has set up a temporary batcave for them, batmobile included, and Barbara Gordon (Yvonne Craig) tags along as well, which means Batgirl will show up as well – the trio’s secret identities seem to be getting closer to being discovered by one another.

There’s not a lot really going on in the episode, there are lots of setups, as Batman and Robin visit with Ffog, who is already aware of their arrival in Londinium, and is prepared to stop the Dynamic Duo, something which closes out the episode as Ffog’s house staff ambush Batman and Robin – Batgirl shows up to lend a hand – though the baddies slip a fog bomb into the batmobile which triggers when the Dynamic Duo return to their Londinium barcave!

The Foggiest Notion was also written by Allen and Hoffman and was first aired on 30 November, 1967.

Our heroes apparently escaped the fog bomb thanks to some extinguishers placed in the batcave, which all happens off-screen and is related to the audience when Batman and Robin join Gordon and his Ireland Yard counterpart, Watson (Maurice Dallimore).

Batman and Robin find themselves walking into a trap at the Three Bells pub, while Batgirl goes to investigate more of the Girls Finishing School. Everyone ends up in trouble, Batgirl is paralyzed and is taken off to the dungeon, while Robin is chained to a bridge raising winch, and Batman’s memory is wiped clean by an insidious device of Ffog’s.

Fortunately, Alfred is able to rescue Batman, and restore his memory, thanks to a handy bat-gadget, and the pair are able to rescue Robin, but not before Ffog shows up with his men, and his fog pipe, to make the situation a little more cloudy.

While our heroes stumble through the fog, and Batgirl remains chained in the dungeon, the audience is left to wait for a conclusion to the escapade, and hopefully it doesn’t all happen off camera between episodes.