The story begins with 8 guests invited to a mansion on an isolated island. They are all strangers to each other, and none knows their host, Mr. Owens, who has yet to arrive. The only other people on the island are the two servants, Mr. and Mrs. Rogers. After dinner Mr. Rogers puts a record on, as he has been instructed by the absent Owens to do, and on it is a voice accusing everyone present, including the servants, of being murderers who have escaped any punishment for their crimes.
That's quite the shock to them all, and all the more so when one of them admits he is indeed a murderer, and then, after taking a drink, promptly keels over and dies. He's been poisoned, and it seems their "host," Mr. Owens, has invited them here to exact his own form of justice on them all.
But how has he done it? After all, it's clear there is no one else on the island. That's when the remaining 9 realize that one of them must actually be Mr. Owens. From then on it is a murder mystery and not so much a whodunit as a whoisdoingit, as others are also killed, though almost always off screen.
There are a lot of mysteries on TV today that revel in the darkness, and the gore, and the violence of murder. Another sort is about the investigator methodically, and sometimes brilliantly, putting the pieces together so as to bring the bad guy to justice. We should stay clear of the former because it presents evil as good, while the latter can be enjoyed. While And Then There Were None is gore-free, and has the violence taking place off-screen, it isn't clear for almost the whole film long whether there even are any good guys. So one caution would be that while this isn't dark like some of today's murder shows, it also isn't a heroic tale like Basil Rathbone's Sherlock Holmes. It is somewhere in the middle, and that might be too much in the wrong direction for some...though I would not agree.
The other caution would be that the only character to quote Scripture is a hypocrite. But she isn't the only one.
Director René Claire demonstrates that is possible to "tell and not show" violence and still keep things suspenseful. Though this it is tame by modern standards, the suspense means it is still only for only adults, and only those who appreciate a good mystery.
The copyright for And Then There Were None was allowed to expire, so it is now in the public domain. That's why you can watch it, for free, in black and white below. A colorized version is also available for free, here.