We're back under the sea and at the mercy of underwater aliens called the Aquafein.  Barbara, inevitably, has to be rescued by Ian with a ray gun and the Doctor then declares they must escape 'to another Age'!  And there the story ends!  It's all a bit odd.

Decided to do all 16 stories of these I think there basically Ian 1st and Barbara stories the final 2 retell the webplanet with just those 3 but over all there not the best but I think if I was from the 1960s I’d love them