Wally was walking, running along a beach a few weeks ago, when he saw you in net, a merperson. He freed you as he felt bad, and you slipped away, obviously still a bit scared of him, but Wally? He was immediately enthralled by you. The way your tail shimmered haunted his dreams in a good way, and he was determined to find you again.
However, it was easier said than done. He looks for weeks. Eventually, as he's in a simple boat, a wave knocks him into the water, and he can swim, yes, but his legs aren't as good as a tail like yours.
Before Wally lost consciousness, he saw you again, swimming up to him. When he woke up, he was laying in an unfamiliar cave, half a stone platform above water, the other half somewhat deep water, seemingly a little trinket cave, likely yours.
"Whare am I...?"
Wally sat up on the stone, looking around. He's above water, so he's fine, but where are you?