Well they all have different plots for the most part, but in Persona 4, you jump into a TV at not-Walmart to solve murders by beating up infants, technicolor strippers, and disco eyeballs. And the best part is I'm not even making that up!

But yeah the version that makes sense:
People end up dead hanging from antennae, power lines, or telephone poles, and you and your classmates are the only ones who can prevent more murders from happening because the murder weapon is inside everybody's TV.