Dave is deaf, and Wally is blind. They witness a murder, but it was Dave who was looking at her, and Wally who was listening. (IMDb)
The premise is one that could be completely butchered if handled the wrong way, but fortunately, Pryor and Wilder have good comedic timing and chemistry together and even add some welcome sensitivity and humanity to their respective characters (see their bench convos). Unfortunately, not every scene lands, and the dud gags get more frequent as time goes on (gotta love that casual sexism..). The plot is pretty poorly written too, especially in the gong show of a final showdown and resolve.