Help me with this puzzle Look at this puzzle:

[FEN "r3q3/1pb1rbk1/2pn1p1p/p1Qp1Bp1/3P4/4P1NP/PP3PPB/3RR1K1 b - - 0 1"]


The aim of the puzzle is: Black to play and attain a good position. But I can't find a good position here. Then I looked at the solution, which was 1... Nc4!! . But I can't understand what happens after this move. I think both sides are equal. Can anyone help me?
Black will trap the queen on the next move, either with Bd6 or b6. For example:

[FEN "r3q3/1pb1rbk1/2pn1p1p/p1Qp1Bp1/3P4/4P1NP/PP3PPB/3RR1K1 b - - 0 1"]

1... Nc4 2. b3 Bd6 3. bxc4 Bxc5 4. dxc5 dxc4


and with a queen and a (passed) pawn for two minor pieces, Black will have no problems to win this game.