Quaid will play a "bitter detective" (is there any other kind?) grieving over the loss of his wife. In the meantime, he is investigating a crazy murder case, as detectives so often do. However, while he is investigating the case he discovers -- ready for this -- "a shocking connection between himself and the suspects in a serial killing spree linked to the Four Horsemen of the Apocalypse." What exactly this means we are currently left to guess, but I'm pulling for Dennis Quaid as the long-lost fifth horseman, Mildew. C'mon ... Death, War, Famine, Pestilence and Mildew.
If it were up to you to add a fifth horsemen for Quaid to portray, who would it be? I know somebody out there wants to throw down a Terry Pratchett "Mr. Soak" reference, so go for it.