The final programme in The Dark Side of Modern Love examines asphyxiophilia, or 'breath control play', a practice involving asphyxiation that can deliver heightened sexual sensations, but can also result in death. The film features contributions from psychologists, sexologists and devotees of the most dangerous sex game of all and follows the tragic consequences that can occur when it all goes wrong. Death by Sex looks at the risks involved and how far-reaching the consequences can be for those who begin as loving partners and end up criminals. Steven is currently serving seven years for the manslaughter of a gay lover who crossed America to experience breath-control; Robbie has recently been released after serving a nine-year sentence following the death of his long-term lover; and Joseph's third wedding anniversary night ended in the death of his soul mate.