Stephen King's The Mist

Set in a small town, a mysterious mist descends upon it, trapping a group of inhabitants inside a supermarket. Once they realise that there are other-worldly ''things'' in the mist, they are loathe to leave the safety of the store. They need to rely on and trust each other to deal with what is outside, but as the situation develops, true colours emerge and the people inside may be more dangerous than whatever is out there...