Check: our hero tightens the net by bringing the rook to A8.

From the dark, Alpha Bat pushes the bishop to B8, and our hero's king takes E2, leaving E1 behind. Alpha Bat answers by moving the rook from D3 to G3, while our hero slides the king across the board, from E2 to F2.

Alpha Bat gives check with the bishop on E3.

With a steady hand, our hero brings the king to E2; then alpha Bat's rook advances from G3 to G6. And it is checkmate: our hero ends the game on B8.