Splash, Too is a made-for-TV sequel to the classic Daryl Hannah & Tom Hanks Splash film. It follows the continuing love story of Madison the mermaid and Allen the human and so features their return, but all the main characters have been completely recast.
At the end of Splash, Allen helps Madison escape from the research facility. Madison can't stay anymore, and Allen makes the choice to follow her despite her warning that he can never return. The last shot is of them swimming together towards what looks like an underwater kingdom. In Splash, Too, some of those aspects have been done away with and instead Madison and Allen are living on a deserted island together. Although Allen's still very much in love with Madison, he's rather bored by his new home nad isn't dealing with the culture change too well. Madison explains that they can go back to New York (just roll with it), which has Allen thrilled.
Back in New York, Allen tries to revive the family business with his brother, Freddie, and Madison tries to adapt to being a housewife. The emotional plot is pretty much like the old Bewitched TV series, where the lady with an unusual past tries to adapt to her human husband's lifestyle and stay hidden but can't help let her true side come out. There's even the nosey neighbour who keeps getting glimpses of the weird goings-on but can't get anyone to ever believe her. (I half-expected the neighbour's husband to be called Abner). There's also some I Dream of Jeannie thrown in there, due to Madison's constant misunderstanding of human idioms and metaphors.
Amy Yasbeck (whom I will always remember from The Mask) doesn't have the otherworldlyness or swimming skills of Daryl Hannah, but she's adorable as literal fish-out-of-water Madison who finds a mission in helping her dolphin friend, Salty, because Allen isn't the only one who needs a cause to believe in. The underwater scenes are also even more brief than the first film since Madison spends almost all her time on land, so we don't get to see her in her element as much.
Randomly, the Splash franchise is owned by Disney (via Touchstone Pictures), so I had a laugh at the use of Snow White's "Whistle While You Work" during Madison and Allen's home-redecorating montage.