There's nothing like a good murder mystery, and writer Agatha Christie certainly made a career out of them. But while Christie penned 66 detective novels and several plays, I stop short of calling her an expert at the mystery genre. While mystery depends on surprises, Christie often uses conventional devices, and that's the only problem with Austin Playhouse's otherwise stellar production of And Then There Were None. While the company gives it their all, there's a lingering feeling that you've seen this before.