The story is about 2 guys named Eithen and Ricky, who get teleported into an Anime universe from an experiment gone wrong, and they go on these wacky adventures to find their way back to the real world, right now they are in the One Piece realm, and Eithen is playing this song on his guitar
https://www.youtube.com/watch?v=GIh3Rn-WwFA

and it looks like Eithen is getting his attention from Boa Hancock, she wants to kidnap, Eithen and Ricky, and force them to perform music on her ship.

I do not own One Piece or any of these characters, except for Eithen and Ricky.