The Queen and Bishop are there to provide back-up for the Knights but it's the pawn that sneaks up from the shadows to prevent the escape. This is a marvelously complex puzzle for a mate in two scenario. Very nice indeed.
I thought I had this solved, considering it a zugzwang position - except at first I did not notice that if for example White plays a waiting ove such as 1. g6 or 1. Bb7, Black escapes mate in 2 by 1...Rxe3! Until I realised that, I was convinced it was a puzzle with several solutions. Once I saw that, it was clear that the key move had to provide a second attack on d4, even at the cost of exposing the N on d3 to capture.
First, I saw that if Black plays 1...Kd5, 2.c4# is mate. I also saw 1.Bb7 and, after 1...Rxe3 cleared the d4 square for the black King, I realised the solution.