From its starting position, the white knight that captured the black queen has moved exactly eight times to get where it is now. How is this possible?
When a knight moves, notice that it always moves from a white square to a black square or vice versa. Therefore it is impossible for this knight to have started on b1 (a white square) and reach its current black square in eight moves.
But there’s no requirement that this knight started on b1! In fact, this knight started on g1 (a black square), and the other knight moved to g1 later.
One of many possible sequence of moves is: Nf3, Nd4, Nb5, Nd6, Nf5, Nd4, Nc6, Nd8 (with the other knight moving Na3, Nc4, Ne5, Nf3, Ng1 somewhere in between).