Lunchtime toddling tactics -- Cool mating pattern!

I've gotten into a habit of late of practicing tactics at lunchtime.  Sometimes I totally bomb and other days, I do well.  This was one of those in between days but I came across a nifty little tactics puzzle that very nicely demonstrates a sneaky mating pattern. 

Now this shouldn't be too difficult for you stronger players.  But remember, I'm still a tactics toddler.   :)  Always good to review these patterns though.  :) 

I don't want to give any hints so give it a go and we can discuss it in the puzzle.