agb2002: Black threatens g4.
White can attack the black king with several pieces starting with 15.Rxe6+:
A) 15... fxe6 16.Qxe6+ Kf8 17.Qxh6+
A.1) 17... Rg7 18.Nxg5 Re8 (due to Ne6+) 19.Ne6+ Rxe6 (19... Kf7 20.Nxc7 Re1+ 21.Bf1) 20.Qxe6 Bxh2+ 21.Kf1 Re7 (21... Rf7 22.Bh6+ Kg8 23.Qg6+ Kh8 24.Qxf7 wins decisive material; 21... Bf4 22.Bxf4 Qxf4 23.Qxd7 wins decisive material) 22.Bh6+ Ke8 (22... Rg7 23.Bc4) 23.Bg6+ Kd8 24.Qg8+ Nf8 25.Qxf8+ Kd7 26.Bf5+ Re6 27.Bxe6+ Ke7 28.Bg5#.
A.2) 17... Kf7 18.Bc4+ Ke7 19.Qe6+ wins decisive material.
A.3) 17... Ke7 18.Qh7+ Kf8 19.Bxg5 (19.Bc4 Nf6)
A.3.a) 19... Nf6 20.Bh6+ Rg7 21.Qh8+ Ng8 22.Bc4 is winning.
A.3.b) 19... Rxg5 20.Nxg5 Ke8 21.Qf7+ Kd8 22.Ne6+ wins.
A.4) 17... Ke8 18.Qe6+ Kf8 19.Bxg5 must be winning. For example, 19... Re8 20.Bh6+ Rg7 21.Bxg7+ Kxg7 22.Qxe8. Or 19... Rxg5 20.Nxg5 Nb8 21.Nh7+ Kg7 22.Qg6+ Kh8 23.Nf6.
B) 15... Be7 16.Rxe7+ Kxe7 17.Qxh6 looks very good for White.
C) 15... Kd8 16.Rxh6 g4 17.Qh4+ Be7 18.Bg5 Bxg5 (18... gxf3 19.Bxe7+ followed by Bd6 looks very good for White) 19.Nxg5 wins two pawns.