(Most other film adaptations, while still using an upbeat finale, have significantly toned down the action-packed climax Christie used in the play.)
Things turn ominous: First their native guides abandon them, then cut the bridge line (their only way in and out of camp).
Following their dinner, by means of a gramophone recording, an inhuman voice accuses each person of a murder that they had caused, for which they had escaped justice.
In the morning, Rodgers' wife Ethel Mae is found dead in her bed (possibly from an overdose), fulfilling the second line of the rhyme.
As four of the men set off with rifles to hunt down Mr. Owen, General Romensky is pushed off a cliff and dies.
She returns to the common tent where Wargrave, alive, is waiting, wearing his judicial robes and wig, with a noose prepared for her to fulfil the last verse of the rhyme.
He forces Vera at gunpoint into the noose and explains how Dr. Werner helped him fake his own death so he would be free to spy on the rest of the party: the "red herring" from the rhyme.
He pulls the chair out from under Vera and watches her struggle in glee as he drinks poisoned wine to kill himself as well.