At first glance, it seems odd that White, a queen up and having a passed pawn on the seventh rank, should be asked only to draw, but a more detailed inspection reveals a huge problem. There is a threat of Nb7+, which will mate or regain the queen. If White tries to avoid this by moving his knight to create an escape square on e8 for his king, then 1 . . . Nf6 discovers a queen-winning check.
We need a little inspiration, and a suspension of mental blocks, to find the only move that even gives a chance of prolonging the game, and that is the brilliantly desperate 1. Qa8+]] giving White a little breathing space after 1 . . . Kxa8. But what then? 2. Nxc7+ Kb7 is hopeless. 2. Kc8 looks promising with its threat of Nxc7 mate, but after 2 . . . Nf6 the White knight is pinned and 3. d8=Q loses to Rxe8. This is rather discouraging, but there is one move left to consider, so it has to be correct.
So we plough ahead with 2. Kxc7, abandoning, for the moment, the idea of Nxc7 mate, but instituting another mating threat in d8=Q. Since 2 . . . Nc6 would be met simply by 3. Kxc6, Black must stop the threat with 2 . . . Nb7, leaving White scratching around for another brilliant idea. The only two weapons in his armoury are d8=Q, and Kc8 together with Nc7 mate. With 3. Kc8 again met by Nf6 and 3. d8=Q met by Nxd8, it does not look promising, but blurring the two images together gives the right idea: 3. d8=Q+] Nxd8 4. Kc8]
Thanks to the knight so delicately lured to d8, 4 . . . Nf6 no longer creates a pin, so Black must instead protect c7 with 4 . . . Ne6. Now we are ready for the beautiful finish.
A rook, a knight and three pawns behind, White plays the quiet 5. a5] Black dare not move his knight from e6, but has only one other legal move, 5 . . . Nf6, and it is therefore a draw by stalemate.