White to move, checkmate in 5 moves.
FEN: 6r1/p3p1rk/1p1pPp1p/q3n2R/4P3/3BR2P/PPP2QP1/7K w - - 0 1
Alternatively, the more obvious 6 moves solution (because who counts when they find a mate!):
4. Rxg4+ Qg5 5.Rxg5+ fxg5 6. e5#
Also a nice play... I suppose the pivotal move in both solutions is e5.