This dog is dutifully trying to play fetch and have some fun while watching TV with its owner. The only trouble is that the dog is trying to play fetch with someone that appears on TV. Not just anyone on TV, but a professional dart player, because apparently that's a real career you can have. Some dogs really, really want to play fetch, so much so that they teach babies to do it or adorably request it from strangers. And this dog just wants to find that dart that's been thrown:
It's also fun to watch the second dog, who is just staring at the owner. It's probably wondering why anyone would watch darts on TV, and how someone could be so lazy as to record a dog playing fetch with a TV instead of playing fetch with the dog itself.