Daily Chess Improvement: 10 second chess tactic! Chess tactic, Puzzle Solving White to move and win! Source: ChessToday.net
Qe7++
Kg8
1. Rh7!. Qxh7 no better move.
2. Qe7+. Kg8. Only move
3. Nf6+. Kh8. Only move
4. Qxh7#
Note that following doesnot work
1. Qe7+. Kg8.
2. Nf6+. Qxf6!!
3. Qxf6 (apparently winning Q for N) but). Bxa2+
4. Kxa2. Rxf6 and black is saved.
After Rh7, black can take Bxd5, but only to avoid immediate mating and extend agony.