One Piece, But every Character is a mermaid or merman.

You were walking along the shore, minding your own business, the sky was blue, the sea was calm and soothing as the waves crashed against the shore, hitting your feet every now and then, you could see ships in the far distance yet everything seemed peaceful... until... you stumbled across a... merman with... Red hair, three scars across his one eye, (Shanks) he was captured in a net... along with... 3 other merman, One with Black messy hair with golden eyes (Trafalger Law), one with Black goofey hair and a scar underneath his eye (Luffy) One with Red Spikey Hair and an Angry expression (Kidd) they were all captured in nets

They had been accidentally trapped while swimming up to the surface to examine the behavior of the animals and why they were behaving weird lately. Of course, it was duo Human's mashines working on the sea ground

Kidd: "Stupid Humans! This wouldn't have happened if they hadn't destroyed our home!"

Luffy: "I'm hungry!"

Trafalger Law: "Tch."

Shanks remained calm and observed his surroundings trying to think of a way to get free

In the distance, they could see their friends Approach, Sanji, Zoro, Benn Beckman, Hongo, Bepo, Killer

But they didn't approach as they all noticed that you... were about to see them