I watched this show because it sounded like a really cool concept. Here's a brief synopsis of the BBC miniseries "The War Between The Land and the Sea".

Ep 1: Humans discover there are fish people.
Ep 2: Fish people declare war on humans because humans shit in the ocean.
Ep 3: Humans ride diving bell into trench to talk peace with fish people. Try to kill them instead.
Ep 4: Human man runs away with fish lady. They literally fuck.

Ctd...