Plot and Summary of this verse
This verse follows a teenager named Yusuke Urumeshi who, through a series of unfortunate events, becomes a spirit detective and basically hunts down demons causing trouble and along the way is joined by his close friend Kuwabara and then Hiei and Kurama who helps Yusuke on his spirit detecting quests.
Power of this verse
Yu Yu Hakusho in terms of power is above One Piece and Bleach, but below Naruto now (due the Narutoverse got crazy asspulls powers up). There was a time YYH characters were often used in battles against DBZ characters, due that both had similar fighting styles, but unafortunatelly YYHverse doesn't pack the power to really contend to DBZ even at the Saiyan Saga. Mostly End of DT (Dark Tournament) characters are mid tier One Piece level and end of series characters such as Yusuke are able to possibly continent bust and lower tier characters such as Sensui are able to possibly country bust, which leaves this series with multiple Alpha Level Mutants but nothing more powerful than that I'm afraid.