White to move!
Dave, black can prolong things with 4......Rf1, but he then has to still give up the rook for the bishop, I suppose.
- Rg7+! Kh8, 2. Be6 Ra1, 3. Rg8+ Kh7, 4. Re8! Ra6, 5. Re7+ Kh8, 6. Kg6! Rxe6+, 7. Rxe6 and White mates next move.