Torihada 2: yofukashi no anata ni zotto suru hanashi wo(2007)

For no apparent reason, four strangers find themselves with a rope around their necks, balancing on an unstable chair. They will quickly realize that each of them has the code to remove the padlock blocking the rope of their left neighbour. But just when they were about to exchange the codes, one of the four people will make a revelation with serious consequences...