A bit easier than your previous ones, but still challenging. Lets see here:

Ra6, Qb8 (the whhite castle at b8 is such a threat that black queen needs to take it out)
Re6, Qb4 (white is one move away from checkmate. so queen focuses on white king to buy time)
Ke2, Qf7 (white king can't be threatened so black queen moves to protect black king. any other move will lead to checkmate next turn)
Re8, Qe8 (black queen can only kill white castle at this point)
Be8... (at this point, black has nothing except pawns and a king. White has a bishop and a rook. Game over eventually .

I realize this isn't the fastest strategy so I'm going to keep thinking.