"Murder With Mirrors" leaves one more depleted than a case of the flu. An intolerably static, stuffy TV movie based on yet another Agatha Christie mystery (is she still alive, or what?), the CBS movie, at 9 tonight on Channel 9, unites Bette Davis and Helen Hayes for the first time in leading roles, but the film is so decrepit, they both fall through its creaks.

Davis makes her first movie appearance since the series of illnesses that forced her to drop out of ABC's "Hotel" in 1983. She looks frail, and her facial features were affected, but there's still regality there, and since she plays a woman who may, or may not, be getting a daily dose of arsenic from a would-be assassin, frailty is in character.

Hayes, on the other hand, makes a plump and dumpy Miss Marple, pulling out all the stops in the cuddly adorability department until a viewer wants to beg for mercy; she must make self-respecting dowagers cringe with embarrassment. Warner Bros. publicity circulates the rumor that Hayes has decreed this to be her last starring role. Can we get that in blood?

The real star of the film is Brocket Hall, a historic beauty set on an estate 20 miles out of London and here impersonating Stoneygates Hall, where murder be done. The home and the grounds are strikingly handsome. Unfortunately, the actors show less animation than the furniture, and the director, Dick Lowry, apparently felt it his duty to see that no one got out of hand and ventured into realms of energy or credibility. At times during this tedious antique you feel for all the world like you're watching a Christie production by the community theater of Banff, and you wonder that the scenery doesn't fall down on the actors' heads.

Ersatz Christie like the current CBS "Murder, She Wrote" series, doddering as it is, may be preferable to actual Christie so listlessly attacked. In addition, the current PBS "Mystery" series of Christie short stories is much more intelligently done and reveals a refreshing departure for Christie from the tired detective tale with the suspects all gathered neatly in a room for the usual tidy wrap-up.

George Eckstein, also the executive producer, wrote a perfectly miserable script, so toploaded with exposition -- much of it reeled off by a breezy redhead (Liane Langland) driving a sports car -- that there seems no hope of ever making sense of it, and no desire to do so, either. Besides, her jabbering goes on over heavenly aerial shots of the English countryside, and sullies the view. John Mills, Dorothy Tutin and Leo McKern also appear, and they're sullied, too. It is, in fact, a very sully movie.