The Wrong Box (1966)
A tontine is established for twenty boys in 1818 England – a tontine being a kind of insurance wager in which money is invested by each participant, to grow with interest, with the last survivor to get the substantial payout. We watch the group dwindle until only two elderly brothers are left in 1882. One brother is watched by his nephews who will keep him alive at all costs; the other lives in ill health and poverty as the only support of his perpetually confused grandson. Statues and bodies are switched, in the wrong boxes, until everyone is sure that one (or both) of the brothers has died. Now if they can only make it seem as if the other brother died first, over a hundred thousand pounds (in Victorian England, when a pound was a pound) will be theirs.