1. Qb4

(The Queen moved from e7 to b4.)
Black has many possible replies, but none stave off mate on White's next move. Here are some possibilities:

1. ... Bxb4 to which White replies:
2. Ng4#

1. ... Ke3 to which White replies:
2. Ng4#

1. ... Qxc7 to which White replies:
2. Qd4#