A guy in an apartment watching another guy with a bin bag on top of his head and another fashioned into a sort of cagoule, pretending to be a fly. Going awowowowow against a window in that way that a fly might. Caption reads when you open the window to let the fly out. As he opens the window, the fly guy looks at him then defiantly moves away from the open window, continuing his awowowowow against the closed window as another 'fly' (guy with bin bag on his head) flies into the open window and then joins the other one as they turn and smile defiantly at the non bin bag man and then continue upon their collective awowowowow against the closed window until the nonbinman pulls out a tiny tennis racket (probably a bug zapper) which scares them off. We find the humour in the absurdity of the cheeky bin bag flies doing that thing deliberately to annoy us. Which of course they do not.