Error in Lesson 3 of Master: Attack and Defence

http://www.chess.com/chessmentor/view_lesson?id=6890

The puzzle asks to attack the black king. I played Nxh7 first and it says "Correct Alternative move!" and elaborates: "now try again by making the move you'd make after Kxh7". 

I play Qh5 and...wrong! But I did exactly as you asked! 

The position for those who can't open link: I am castled queenside, rooks on d3 and h1, knights on e4 and g5, queen f3, pawns on f2,g2,h2. Black: castled kingside with untouched pawns, queen on c7. That's all that's relevant.

My explanation: after Nxh7 Kxh7 I would've played Qh5+ Kg8 (forced) Nf6+ gxf6 (forced or mate) Rg3+ Qxg3 (forced otherwise mate) hxg3. Now Qh8 mate is unavoidable with my h1 rook, h5 queen, his g8 king, pawns on f7,f6 and rook f8.

That's because they wanted you to go back to the original position.  Qh5 isn't the right move in that position.