Figure[White to move]

Your knight is threatened by the pawn on e5, but don’t retreat without inspecting your offensive options. First point to see: White’s queen and rook aimed at h6, and prevented from mating there only by the Black queen on b6. Second thing: White can put an interfering piece on the sixth rank with protection by playing Ne6. If Black plays BxN or f7xN, then of course the rank remains blocked and White mates right away on h6. If Black plays QxN, he loses his queen to f5xQ—and then has to spend yet another move replacing the protection of h6 that the queen had provided; so he plays Rg6, and now loses his d7 bishop to the same pawn that just took his queen. It’s an ugly result, but the best Black can do.