Amir Khan and Gaby Roslin look at the cases of a woman who has restless leg syndrome, and a man who has had chronic insomnia for 20 years. Elsewhere, the sleep deprivation experiment continues, setting up a mini casino to test for risky behaviour, pain resistance and emotional control. Finally, as the subjects reach the final hours of the challenge, the experiment begins to take its toll as the participants' emotions go into overdrive, with one threatening to quit altogether. Last in series.