Before White’s knight begins its epic journey, it’s important to note that Black has to defend against the capture of the a-pawn, g-pawn and even the h-pawn. All of Black’s subsequent moves should be seen as a desire to defend against all of the knight’s marauding intentions.
1. Nf2 Ke3 2.Nd1+
2.Kg2 Kf4 3.Nd3+ Kxg4 4.Nb4 Kf5 5.Nc6 Ke6 6.Nxa7 Kd7 7.Nb5 Kc6 8.a7 Kb7 and Black draws easily, even without the kingside pawns.
2…Kd4 3.Kg2! Black is caught between a rock and a hard place as the knight will play to f2–h3xg5 or c3–b5xa7 depending on the direction the king chooses.
3.Nb2 Kc3 4.Na4+ Kb4 5.Nb6! Kb5 6.Nc8
6.Nd5 Kxa6 7.Nc7+ Ka5 8.Ne6 nabs the g-pawn just the same.
6…Kxa6 7.Nd6 Ka5
7…Kb6 8.Ne4 a5 9.Nxg5 a4 10.Ne4 a3 11.Nc3 followed by pushing the g-pawn wins as in the main line.
8.Ne4 Kb4 9.Nxg5 a5 10.Nf3 a4 11.Nd4 Kc4
11…Kc3 12.g5! Kxd4 (12…a3 13.Nb5+) 13.g6 a3 14.g7 a2 15.g8Q a1Q 16.Qg7+ wins.
Or 11.Nc2 Kb3 12.Na1+ Kb2 13.g5.
12…a3 13.g6 a2 14.Nc2 Kc3 15.Na1!
After 15 straight moves, the knight has arrived at long last at its final resting place. What a hero’s journey!
15…Kb2 16.g7 Kxa1 17.g8Q Kb2
Normally, the a-pawn would draw, but unfortunately for Black the pawn on h4 spoils the dream.
18.Qb8+ Kc2 19.Qa7 Kb2 20.Qb6+ Kc2 21.Qa5 Kb2 22.Qb4+ Kc2 23.Qa3 Kb1 24.Qb3+ Ka1 25.Kg4! h3 26.Qc2 h2 27.Qc1 mate!